Even tenured professors should fear backlash from social justice warriors for holding the "wrong" opinions.

Rajshree Agarwal wrote in the Washington Post about how, when she was an assistant professor, she would challenge anyone if she thought they were wrong. But now, even though she has tenure, the climate on college campuses is so volatile that she is afraid to speak up, lest she find herself on the wrong end of a social justice mob.

She tells the story of a gala she attended, which had a burlesque theme. She enjoyed the performances, but the conference director was nervous that people would complain about one performance, which she described as a "mini striptease."

"Sure enough, a critical post soon appeared on Facebook from a champion of gender inclusiveness — a gay woman who hadn't seen the show but had learned about it from a friend," Agarwal wrote. "Like-minded thinkers quickly added their comments, and some called for a boycott of the society."

How typical. Someone complains about something they weren't even present for, and others chime in. It's classic Internet outrage. Also notice the subtle sexism in the approach: A woman who wasn't at the event deciding she needs to step in and defend the women who were in attendance — who weren't complaining.

Agarwal said she wanted to speak up and to say that she is a woman and she loved the show, but she didn't speak up.

"People often discuss academic freedom in the context of the First Amendment, which prohibits prior restraint imposed by heavy-handed governments," she wrote. "The spiral of silence is something different, and perhaps an even greater threat to the human spirit that drives innovation."

Agarwal also noted a recent moment at an academic conference where she was asked how businesses could "create social value." She replied: "They can do good business."

Instead of civil discourse, two of her colleagues began trying to discredit her by tying her to free-market capitalists (one of the top enemies of liberal academia). One colleague remarked: "Milton, Friedman, are we?" And another pointed out that Agarwal had worked for an organization that was funded in part by the Koch Brothers.

"People need filters. Self-regulation is part of emotional intelligence and necessary for reasoned and respectful discourse," Agarwal wrote. "But the distinction between self-regulation and self-censorship becomes blurry when a culture of fear silences opposing viewpoints in higher education."

Trigger warnings, safe spaces, disinviting speakers and otherwise shutting down the free exchange of ideas is not helpful in the long run. People need to be able to freely discuss difficult topics instead of merely hiding from them and pretending they don't exist in order to "win" the argument.

Ashe Schow is a commentary writer for the Washington Examiner.