On Oct. 7, Columbia Business School Prof. Shai Davidai posted videos of himself following a university administrator around and asking him why anti-Israel protesters were allowed on campus. And the same day, a campus pro-Palestinian group praised “armed resistance” against Israel and celebrated the Hamas attack on it last October. So which of these actions violated Columbia‘s new rules around free speech? Arguably, they both did. Davidai’s behavior ran afoul of the ban on saying anything that “defames a specific individual.” And the statements praising violence against Israel broke the rule prohibiting speech that attacks “group identity based on race, ethnicity, national origin, religion, etc.” But only Davidai received a sanction from Columbia, which barred him from campus until he completes a training on university policies. And those same policies have not been invoked to penalize the pro-Palestinian group. That speaks volumes about how Columbia — and other universities — have lost their way on free speech. And the only way to get it back is to give everyone their say, even when it hurts. Start with Davidai, who had already been temporarily barred from parts of campus back in April after he tried to stage a sit-in on the lawn where pro-Palestinian protesters had erected an encampment. In an email exchange that Davidai posted, university Chief Operating Officer Cas Holloway told Davidai he couldn’t go there because of risks to “safety.” Now, officials have prohibited him from the university entirely after he posted video of himself confronting Holloway about demonstrators who protested a memorial service on the one-year anniversary of the Hamas attack. “How did you allow this to happen on Oct. 7?” Davidai asks Holloway on the video. “You have to do your job. And I will not rest if they won’t let us rest.” Davidai called the protest “horrific and unbelievable,” But he also acknowledged that it was “free speech, no matter how painful it is.” Columbia made no such concession about Davidai’s own behavior, which it said wasn’t speech at all. “His freedom of speech has not been limited and is not being limited now,” a spokesperson insisted. Instead, the official added, Columbia penalized him for engaging in “intimidation” and “harassment.” That’s sophistry, plain and simple. Posting the video of Holloway was obnoxious, to be sure. But if the university can prohibit anything it finds annoying or distasteful, freedom of speech is a dead letter. And censorship inevitably raises the specter of double standards. On Oct. 7, a group called Columbia University Apartheid Divest posted an essay praising the Hamas attack as a “moral, military, and political victory.” It also distributed a newspaper promising “Revolution Until Victory,” accompanied by a picture of Hamas fighters scaling the security fence to Israel. As if that wasn’t enough, the same group rescinded an apology it had issued in the spring after Columbia student Khymani James declared that “Zionists don’t deserve to live.” James doubled down on his comment, too. “Anything I said, I meant it,” he declared. So let’s review. A professor posts film of himself berating an administrator about anti-Israel protesters, and he gets kicked off campus. But some of the protesters celebrate the murder of Israelis, and they get off scot-free. That doesn’t mean the university should clamp down on anti-Israel statements, however horrific they might be. The answer to a double standard is a single one: free speech for all. Alas, our universities are moving in exactly the opposite direction. At the University of Pennsylvania, where I teach, new speech guidelines require students to give two weeks notice for any demonstrations in heavily trafficked areas of campus. Oh, and we also banned the chalking of university sidewalks. Really. I attended Columbia 40 years ago, when we assumed we could say whatever we wanted. That’s why you went to college: to experience the rough-and-tumble reality of free speech. It wasn’t always pretty, that’s for sure, but it opened our eyes to the world. And we would never have trusted a university official to tell what was so horrific that it had to be kept from our ears. We need to revive that spirit and stand up to the bullies — on the political right and left — who want to censor us. And if you want to restrict speech, too, watch out! One day, sometime soon, the censors will be coming for you. Maybe they already have. Zimmerman teaches education and history at the University of Pennsylvania and is the author of “Free Speech and Why You Should Give a Damn.”