That mob is what transformed this situation from a routine and largely uninteresting ivory tower spat into a dark precedent for academic freedom. Which is what this is. It has become all too difficult to draw clear contours around the new implicit restrictions on academic speech, which would appear to put professors in the distinctly odd position of being less free to criticize one another in print than civilians not crowned with the blessing of tenure.

And, ironically, the original complaint of the student — that he wasn’t allowed to discuss a particular topic because the teacher feared he would offend other students — is likely in part a consequence of the toxic debate environment the online mob has helped create. It is probably not an accident that demands for “safe spaces” and ever-expanding definitions of harassment are features of the same landscape as 4chan and Reddit.

It’s difficult to identify actions that might be taken to rein in the mob that wouldn’t represent a more serious abridgment of freedom than the existence of the mob itself. Hate speech laws present obvious opportunities for abuse, but more libertarian-friendly strategies, like an expansive invasion-of-privacy tort, raise similar fears about a chilling effect on legitimate debate.