That anecdote about the Harvard Law professor. It’s a real anecdote, that appeared in an article by another Harvard Law professor rejecting the notion that law students should be protected from the trauma of having to learn the law of rape through the lens of difficult, close cases. It was presented as an example of an extreme, indeed ridiculous, request by an individual student. There’s no indication that the teacher took it seriously, or that anyone in the administration at Harvard Law School encouraged that teacher or any other teacher to comply with such a request. If you know anything about Harvard Law School, you know that hell would freeze over before the administration did anything like that to a full-time faculty member. (If you are looking for an institution where the needs of the consumer come first, it’s not Harvard Law School.)
Anyway, I suppose that anecdote illustrates that there are, indeed, some trigger-warning crazies in the world. But it doesn’t indicate that those particular crazies are a clear and present threat to academic free speech.