Hearing ‘jews this, jews that’ since birth causes people to want to ‘fit in’ and go along with what everyone else is doing even if they don’t understand it.
I was surprised by how much anti-Semitism existed when I went to high school, because I never experienced it before outside of South Park. For everyone else, it was just normal and understood (even if they didn’t support it.) It really cemented the idea in my mind that most people do things without thinking just to fit in with others.