There’s a saying common in education circles: Don’t teach students what to think; teach them how to think. The idea goes back at least as far as Socrates. Today, what we call the Socratic method is a way of teaching that fosters critical thinking, in part by encouraging students to question their own unexamined beliefs, as well as the received wisdom of those around them. Such questioning sometimes leads to discomfort, and even to anger, on the way to understanding.
But vindictive protectiveness teaches students to think in a very different way. It prepares them poorly for professional life, which often demands intellectual engagement with people and ideas one might find uncongenial or wrong. The harm may be more immediate, too. A campus culture devoted to policing speech and punishing speakers is likely to engender patterns of thought that are surprisingly similar to those long identified by cognitive behavioral therapists as causes of depression and anxiety. The new protectiveness may be teaching students to think pathologically.