Cancel culture has been cancelled by Barack Obama. Rejoice! Now a long-established ritual of social media, to be “cancelled” or “called out” means to be subject to severe public contempt on account of some infraction against morality.

It can spill into lost jobs, broken friendships and public protests; ultimately, it amounts to an effort to declare the victim a non-person, someone intolerable to decent society. No appeals and no rehabilitation.

Speaking last week at the Obama Foundation summit, the former president told his audience: “This idea of purity and you’re never compromised and you’re always politically ‘woke’ and all that stuff. You should get over that quickly.”

Play Video 1:54 Barack Obama takes on 'woke' call-out culture: 'That's not activism' – video

There was a tendency, he said, for the politically engaged – and he was particularly addressing those on the left – to trade in comforting simplicity and the dehumanisation of opponents. His comments hold a lot of gratifying truths, but the most important one is this: cancelling people feels great. “Like, if I tweet or hashtag about how you didn’t do something right or used the wrong verb, then I can sit back and feel pretty good about myself,” he said. “Cause, ‘Man, you see how woke I was, I called you out’.”

For those doing the cancelling, it’s a righteous high, a buzz of benediction, a most holy moment of delight. Because when it comes to the call-out, we can all tell ourselves we’re doing it for the best of reasons.

We want to build a better world. We want to help our fellow citizens correct their error and protect the vulnerable from harm. And how could there be anything mean or shabby about that?

What a load of self-aggrandising bunk. Cancellation is an intoxicating blend of piousness plus power. The online pile-on is a kind of wild justice and participating in its scourging force is a tremendous thrill. Even better if you have the nous to harness and direct that outrage for yourself. The Twitterverse is studded with micro-celebrities of affront who have raised themselves to prominence on a tide of other people’s anger.

If you have a particularly morbid fascination with this stuff, you can watch a portrait of one of them in the documentary Who Is Arthur Chu? (available on Amazon Prime). Chu leveraged a successful run on the US gameshow Jeopardy! into a respectable Twitter following, then segued into leftwing activism, targeting individuals he deems harmful; now, he commands several thousand dollars a time for delivering talks on subjects such as “toxic masculinity”.

Chu claims to be motivated by anger against injustice. But when, in an unguarded moment on camera, he talks about what success means to him, he doesn’t refer to policy or social change: he talks about how he has nearly doubled his number of followers.

The pursuit of purity is not just a wound in civil society, it’s also the opposite of politics

Inevitably, given that he’s a beneficiary of the cancel culture, Chu is one of the most adamant when it comes to asserting that cancel culture is not actually a problem. For its leftwing defenders, the label is a politicised tag designed to delegitimise rightful critique. A widely circulated image from the webcomic XKCD sums up the position. “If you’re yelled at, boycotted, have your show cancelled, or get banned from an internet community, your free speech rights aren’t being violated,” says the stick figure presenting the voice of reason. “It’s just that the people listening think you’re an asshole and they’re showing you the door.”

This is one of those arguments that’s true as far as it goes, but doesn’t go very far. What if there were an argument against yelling/boycotting/cancelling/banning that didn’t consist solely of claims to freedom of speech? (Obama doesn’t refer to free speech at all in his comments, talking instead about the power of conversation to change minds.)

Another defence is to point to the ostracism of unarguably despicable figures as evidence that cancel culture is actually a good thing – a Washington Post op-ed last week cited the calling out of Harvey Weinstein at a recent public event and argued that “critics of ‘cancel culture’ really just hate democracy”.

Well, maybe. But it’s possible to both approve the shunning of a man subject to widely accepted accusations of sexual assault and also worry about the adoption of shunning as a universal tool of activism.

Meanwhile, on the right, there’s a comfortable certainty that cancel culture is a strictly leftish vice.

The rightwing commentator Douglas Murray, invited on to BBC Radio 4’s Today programme to discuss Obama’s comments, described the quest for “wrongthink” as the purview of his ideological opponents. But it won’t be the left squirming in moral horror when someone dares to show up on the BBC sans poppy between now and Armistice Day. (Bonus: Murray got to play the cancel culture victim when the host Nick Robinson challenged him on his past remarks.)

So the right has its cancel culture and pretends to abhor it; the left, less hypocritically but more incoherently, digs in to defend the indefensible.

Obama is, of course, correct. The pursuit of purity is not just a wound in civil society, it’s also the opposite of politics. “That’s not activism. That’s not bringing about change,” he said. “If all you’re doing is casting stones, you’re probably not going to get that far.” But he assumes here that people engage in politics in order to bring about change and I’m not sure that’s true.

As political affiliation becomes more and more a matter of tribal identity, patrolling the borders of the in-group and singling out enemies takes on increasing importance. After all, it just feels good.

• Sarah Ditum is a writer on politics and culture