That doesn't work as well if the culture has been inocculated.
How does one do that?
Well, I don't know if this is still done today, but when I was in 7th or 8th grade, they (school) drove us, by the busload, to visit a concentration camp.
We were shown the lampshades and wallets made of human skin. The place to stand where inmates would be executed during what they thought were medical examinations. And so on and so on.
It is quite possible that the next "Western" genocide will happen somewhere in Europe. But as somebody who has grown up here, I can assure you it won't be in Germany.
I just wish that history was thaught like this everywhere.