Can reading Huck Finn cause PTSD?

Jon Haidt posted a video of a recent talk along with an outline. I think its unfortunate that he doesn't engage much with the main argument for what he calls "Social Justice U." He notes, correctly, that people can benefit from adversity, so shielding students from ideas that scare them or novels that use the N word, is only hurting their education. The relevant part of his outline:

“What doesn’t kill me makes me stronger.” . . . Kids need thousands of hours of unsupervised play and thousands of conflicts and challenges that they resolve without adult help, in order to become independently functioning adults. . . .
Instead they are enmeshed in a “safety culture” that begins when they are young and that is now carried all the way through college. Books and words and visiting speakers are seen as “dangerous” and even as forms of “violence.” Trigger warnings and safe spaces are necessary to protect fragile young people from danger and violence. [thus] universities must choose one telos.

The problem is that, as Jon knows, too much adversity can be a problem. In one of his books he discusses the psychological literature on adversity, growth, and trauma and I think a fair summary would be "if you're not old and the adversity isn't severe, you'll grow. Otherwise it may traumatize you."

Unfortunately, the claim from proponents of "Social Justice U" is exactly that some speakers, novels that use the N word, etc. can cause PTSD or trigger flashbacks. That is why the movement borrowed the term trigger and requests trigger warnings--because they genuinely believe that w/o trigger warnings people might be traumatized by micro aggressions (or macroagressions?).

I don't know enough about psychiatry to know if you can get triggered in a medically meaningful way by scary ideas. My intuition is that the kind of PTSD people experience after a violent rape or serving in armed conflict is probably very different from the kinds of responses people have to a Milo Yiannopoulos. If that is true then universities don't have to choose--they can be safe places and open to diverse ideas. The irony is that I think Jon agrees with me on the danger of scary ideas since he uses mocking quotes around dangerous and violent, yet he presses the opposite conclusion on the compatibility of civility and truth.