Shortly after the London Bridge terror attacks on June 3, prominent left-wing pundit Sally Kohn used the occasion to tweet a defense of political correctness:

Yet only a few days earlier, there had been a flurry of reports on a very different kind of political correctness. Bret Weinstein, a biology professor at Evergreen State College in Olympia, Washington, had been subjected to vicious harassment for objecting to a Day of Absence, in which white people were asked to stay off campus for a day. Amid calls for his firing, Weinstein was surrounded and berated by student protesters and finally informed by the police that it was not safe for him to be on campus. There was very little dignity or respect in the way he and his supporters were treated.

So which is the real political correctness?

Kohn’s defense is certainly not new or unique. A couple of years ago, New Zealand programmer Byron Clark made the same point with a Google Chrome that converted the phrase “political correctness” to “treating people with respect.”

The progressive media loved it. Vox’s Amanda Taub, one of a number of left-of-center pundits who have dismissed political correctness as a made-up problem, asserted that Clark’s “simple experiment” shows “what’s really going on when people complain about PC culture”: It’s just “a cold dismissal of people’s requests to be treated with respect.”

Granted, when you try this trick (as Taub did) on Donald Trump’s statement that he doesn’t have time for political correctness, the result is not only hilarious but also on-target. But mostly, the experiment falls flat unless you’re already convinced. Indeed, a look at the articles whose headlines Clark used for his demo shows that the translation is ridiculously off the mark.

For instance, “The Real Danger of Political Correctness” (Washington Post) was penned not by some white male reactionary but by a progressive feminist, culture critic Alyssa Rosenberg, who argued that attempts to create “bias-free language” — such as “person of size” instead of “obese” — not only leads to “impoverished and clunky” newspeak but also encourages avoidance rather than examination of difficult issues.

“Political Correctness Is Fuelling Homegrown Extremism, Claims Proud British Muslim” (London Daily Express) quoted practicing Muslim Haseeb Ahmed as saying that fear of causing offense made it difficult to talk honestly about Islamist fanaticism and terror groups such as ISIS, the Islamic State. It’s rather ironic that in his defense of political correctness, Clark, a white man, was appropriating, altering, and mocking the words of a woman and a brown Muslim man. You might even say it’s not very PC.

To be sure, the term “politically correct” gets misused. Sometimes, the online hooligans of the alt-right — and their more sophisticated enablers such as disgraced far-right cult figure Milo Yiannopoulos — use it to dismiss any objections to real and overt racism, misogyny, and other bigotries. Sometimes, internet grouches fling the “PC” slur at movies or TV shows that are seen as having too much girl power or minority presence.

But for the most part, when people talk about “political correctness gone amok,” that’s not what they mean. “PC” generally refers to over-the-top outrage at things no one but a hypersensitive fringe actually finds disrespectful, or rigid taboos on opinions and facts that could be construed as offensive, or extreme and punitive intolerance toward any deviation from the one true faith (just ask Professor Weinstein, a progressive victimized by his own).

Here are just a few episodes — some famous, some obscure — from the recent history of political correctness.

All these stories — and there are many, many more — add up to enough of a pattern to suggest some conclusions.

1. Yes, there definitely is such a thing as political correctness or PC culture, built around identity politics and intersectionality — an ideology that views life in modern liberal societies as shaped entirely by an entrenched system of intersecting oppressions and sees all human interaction in terms of oppression and privilege.

Because this ideology is intensely focused on changing attitudes and eliminating subtle, deeply embedded biases, speech- and thought-policing are not just unfortunate excesses of zeal but an essential part of the “social justice” project.

2. While critics of the concept of political correctness often assert that PC doesn’t limit freedom of speech but merely exposes the privileged to criticism from the marginalized, many PC incidents are likely to have a very real chilling effect on speech and expression.

The privileged transgressors often suffer serious career damage, not only in the academy but also in the left-of-center media and the arts and culture scene. The Christakises and Niedzviecki are far from the only casualties:

In the fall of 2015, Mary Spellman, dean of students at Claremont McKenna College in California, was hounded out of her job by protesters because of an email deemed to be racially insensitive. Spellman’s offense: While offering to help a minority student who was having a hard time at school, the dean had written that she wanted to “better serve students, especially those who don’t fit our CMC mold” — a statement some took to imply that people of color don’t belong at the college.

In 2013, science fiction and fantasy author Jean Rabe had to resign as editor of the SFWA Bulletin, the bimonthly magazine of the Science Fiction and Fantasy Writers of America, due to accusations of sexism — despite being a woman. Rabe’s offenses included a magazine cover with a bikini-clad woman warrior (in tribute to classic sci-fi) and a feature in which two male contributors discussed notable female authors and editors in the history of sci-fi and made too many references to some of the women’s looks.

PC also threatens free debate and exchange of ideas by defining heretical opinions as harmful and violent. The effects are particularly baneful when it comes to discussion of contentious issues related to race, gender, and sexual identity. One recent example is the hounding of Rebecca Tuvel, an assistant professor of philosophy at Rhodes College in Memphis, Tennessee, who wrote an article examining parallels between transgender identities and transracialism — the adoption of a different racial identity.

Tuvel, who fully supports transgender rights, was accused of “enact[ing] violence” and causing “harm” by, among other things, using the term “transgenderism,” referring to “male genitalia” and “biological sex,” and mentioning Caitlyn Jenner’s pretransition name, Bruce. The editors of Hypatia, the feminist philosophy journal that had published the essay, issued an apology and stated that “a more effective review process” would have prevented the “harms” its publication had done. Feminist philosopher Kelly Oliver wrote that a number of academics supported and sympathized with Tuvel in private messages while either remaining silent or actually denouncing her in public.

On at least some occasions, the effort to silence politically incorrect speech has turned violent. Last March, conservative scholar Charles Murray, who has been accused of racism for writing about racial differences in IQ, was not only prevented from giving a scheduled talk (on the cultural gap between the white elites and the white working class) at Vermont’s Middlebury College by protesters who would not stop shouting and chanting, he was also literally chased by a violent mob when he left the building. Alison Stanger, the Middlebury professor who interviewed Murray on a livestream held in lieu of the lecture, received a neck injury in the melee.

3. The “crimes” targeted by the PC police are not about deliberate or even subconscious bigotry but about violations of ideological taboos (such as cultural appropriation) and/or far-fetched, paranoid interpretations of innocent words and actions (such as the Confederacy allusion in the slogan “I’d rather be a rebel than a slave”).

Since one of the tenets of PC orthodoxy is that questioning the validity of grievances expressed by the marginalized is itself a harmful microaggression, the accusations come with a built-in presumption of guilt. It doesn’t matter if most members of the same disadvantaged group see no offense.

What’s more, PC has nothing to do with actual social justice: Stopping white people from wearing dreadlocks will not, in any appreciable way, help with the real problems facing the black community, just as banishing the word “crazy” will do nothing to improve the situation of the mentally ill.

In some cases, intersectional PC actively prevents confronting oppression. For instance, since Muslims are defined as marginalized, feminists who speak out against the misogyny of Islamic fundamentalism can be accused of promoting Islamophobia. This leads to such surreal moments as the 2015 controversy over a talk by Iranian-born feminist and ex-Muslim Maryam Namazie at the University of London’s Goldsmith College, where feminist and LGBT groups joined the campus Islamic Society in denouncing the event as a “safe space” violation.

Some critics of the anti-PC backlash assert that there is also a political correctness on the right.

Indeed, Quartz contributor Noah Berlatsky has argued that the right-wing version of PC tends to manifest itself in far more aggressive forms of speech suppression than that of the left. But this claim rests on an absurdly broad definition of PC that includes any attack or intimidation based on political hostility. Berlatsky cites online harassment of feminists and a threat of violence that resulted in the cancellation of a lecture by feminist video game critic Anita Sarkeesian — actions that he acknowledges have been widely condemned, though not characterized as PC — as well as personal attacks by the right-wing website Breitbart.com on social justice activists.

But internet harassment, threats, and personal attacks on opponents exist across the political spectrum (the first two often perpetrated by trolls with no ideological allegiances). They don’t have the institutional backing, the moralism, or the groupthink of PC culture.

Of course, the right has also used social pressure to shut down what it considers to be offensive speech.

In 1998, boycotts helped kill the ABC series Nothing Sacred, regarded as anti-Catholic by some conservatives for its portrayal of a priest who struggled with his faith and questioned Church teachings on sexuality. In the 2000s, critics of the war in Iraq often encountered a nasty backlash that amounted to punishing or muzzling them. The Dixie Chicks, the popular country music band, were targeted in 2003 after lead singer Natalie Maines told a London audience that they were anti-war and were “ashamed” to be from the same state as President Bush; despite the singers’ apologies, they faced a ruinous boycott, and some DJs lost their jobs for playing Dixie Chicks songs. The same year, reporter Chris Hedges, who criticized the war in a commencement speech at Rockford College in Illinois, was shouted down by hecklers who also unplugged his microphone and at one point rushed the stage. Some conservative pundits defended this as nothing more than robust protest. There’s plenty of all-around hypocrisy on free speech.

But there are differences.

What left-wing journalist John K. Wilson calls “patriotic correctness” lasted a short time at the height of pro-war fervor and targeted fairly narrow categories of speech; even the Dixie Chicks backlash was related to the view that a wartime president should not be denounced abroad. (Other outspoken anti-war celebrities, such as actors Samuel L. Jackson and Uma Thurman, emerged unscathed.)

Political correctness casts a much broader net and demands far more zealous compliance — all the more so since the rules are subjective and constantly shifting, so you can never be sure whether you are in compliance or not until you get called out. Not even the worst watchdogs of patriotic correctness have ever hounded anyone over a comment judged to have unintended unpatriotic connotations.

What’s more, much like religious cults and totalitarian regimes, PC culture not only prohibits heresy but also requires active declarations of orthodoxy. In May, pop singer Demi Lovato was featured in a new music video sporting a hairstyle that, from a distance, looked like dreadlocks. After being called out for cultural appropriation on Twitter, Lovato tweeted to explain that her hair was actually styled in tiny twists:

Mic, the self-appointed digital Pravda of PC, declared that the singer had “messed up a little.” Many offended people, you see, “wanted Lovato to not just publicly deny that they were dreads, but also let her fans know that she understands why that would be so hurtful.” Yet, even when pressed, the stubborn pop star refused to admit that those fans “had every right to feel uncomfortable with the idea that Lovato would wear a hairstyle that strongly resembles locs in the first place.”

The Mic article bore the censorious title, “After Being Called Out for Wearing Faux Dreadlocks, Demi Lovato Still Doesn’t Get It.” To which one could respond, “After being repeatedly told that people are sick of PC, Mic still doesn’t get it.”

In the past several years, political correctness has dominated not only the academy but much of the left-of-center press and digital culture as well. It has a strong presence in art and entertainment and is practically the official religion in “geek culture” communities.

The consequences are dangerous in more than one way.

First of all, political correctness by itself is destructive to the liberal project — to reasoned discourse, free exchange of ideas, culture and community. What makes it uniquely injurious is its rising dominance in spheres of society traditionally associated with intellectual openness and pluralism: the academy, quality journalism, literature, and the arts. Until recently, these were the standard-bearers of the Enlightenment ethos, which challenged any attempt to circumscribe the pursuit of truth and freedom of thought and expression — whether by religion, government, traditional social norms, or other forces. PC may not be a novel form of power dynamics, but it is one especially corrosive to a classically liberal system.

Secondly, PC culture also invites an equally or more toxic backlash, led by the likes of Yiannopoulos. The worst of anti-PC culture is exemplified by the racist, anti-Semitic, and misogynistic troops of the alt-right. Of course modern-day “social justice warriors” did not create racism, misogyny, and other bigotries that predate their existence. But too many people fed up with identity politics, gratuitous white- and male-bashing, and overzealous thought- and speech-policing end up being drawn into the web of the alt-right.

Political correctness enables bigotry both by trivializing it — if you can be called a racist for wearing a sombrero on Halloween or a misogynist for admiring sexy women, the words lose much of their bite — and by green-lighting it when it’s directed at “privileged” groups. When comments like “yet another opinion from an old white man” become weapons of choice in what passes for debate in PC culture, the principle that people should not be attacked or demeaned on the basis of race, gender, or other aspects of who they are becomes increasingly difficult to defend.

Donald Trump’s election victory, itself almost certainly aided by the anti-PC backlash, has made it clear that we need to heal our dysfunctional political culture. One necessary step toward such healing is to restore the classical liberal norms of free thought and free speech. That does not preclude rejecting real bigotry and hate, but respect does not require political correctness. In fact, political correctness is the opposite of respect.