Were my opinion might not be needed but.
I know the Nazis were despicable, so are a lot of protagonists in BDSM stories. Real slavery is unacceptable today (except in parts of Africa and southern Asia) but it was the norm for most of human history. The Romans were cruel and barbarous by today's standards but they brought modern civilization to Europe. My point is that some subjects might seem beyond redemption as far as erotica goes but they really just make the story telling a bit more of a challenge for the author. In any event while there are a few universal erotic fantasies, this site seems more dedicated to those that are more unusual and unique, It would be unreasonable to expect them to appeal to everyone. I for one would hesitate to cast stones, but if I were to think of a subject without any erotic possibilities I'd have to mention….uhm never mind
Mad Lews