The reason I felt the need to push back against that statement is because I knew someone that called the Nazis "monsters". I pointed out that the actions of the Nazis and their sympathizers were certainly monstrous, but they themselves were people...incredibly desperate and living in a time of greater ignorance (when certain propaganda was easier to propagate), but still people. There was nothing special about them. It is dangerous to assume another group of people (humans) in another place and another time couldn't be persuaded to commit similar atrocities.
However, that is reality. If you want to represent that sort of social rot in your tabletop gaming campaign, that is fine, but don't cut yourself off from escapism because entertainment at large has convinced you that escapism is "wrong" or "dumb". As Sigmund Freud once said, "Sometimes, an orc is just an orc."
P.S. Should you desire standoffish beings that aren't human, consider making them universally some flavor of Neutral; there's nothing that says a Lawful Neutral/Neutral/Chaotic Neutral group can't be initially hostile/aggressive until they're convinced to calm down.
