In stunning displays of intolerance, violent protesters succeeded in shutting down the Milo Yiannopoulos appearances on Jan. 13 at University of California, Davis and Feb. 1 at UC Berkeley (“Trump Questions Funding After Unrest,” U.S. News, Feb. 3). What we are teaching on campus is the effectiveness of mob rule. We should be clear about what is happening: the suppression of speech based on a political viewpoint. The overt justification for the appalling behavior of the protesters is Mr. Yiannopoulos’s language, which certainly can be offensive. But this is absurd. We lionize offensive speakers and performers on our campuses....