Wait, what? The Holocaust didn't have "themes" -- it's not a Hollywood movie. It was a genocide. The only "theme" to genocide is the purposeful destruction of a particular group of people, not "racism and sexism." The Holocaust wasn't a toxic work environment. It was a genocide.
The images of the Holocaust include nude dead bodies being bulldozed into ditches. You think teenagers shouldn't see those images because they will see naked people? Have you met any teenagers.
Going to school is all about being "forced" to read things. I really didn't want to read Grapes of Wrath, but to pass 8th grade English I had to do it. If parents don't want their children subject to "forced" reading, then homeschool away.