For some people, books about animals could cause 'discomfort' if it was about Lions and Tigers and such. And if you had a fear of flying, any book about airplanes or air travel could be a problem.
So we can't have books about the Civil War if it mentions slavery. And we can't talk about WWII if the Holocaust is included in the discussion. Yet, these same high school students can go home and play 'World of Warcraft' or 'Grand Theft Auto' and that's OK because it's just make-believe, but if we want to talk about something that actually happened, we can't if it makes someone uncomfortable. Well, screw it. If half the class is uncomfortable, all that tells me is that this material should have have been taught to them years ago.