It depends what you mean by "the Nazis". I certainly don't think it's particularly productive to blame the average citizen.

What was the difference between the average person in Germany in the 30s and the average person in any other country at that same point in time? Because if people aren't allowed to be products of their environment, are you saying it was some inherent genetic flaw? What else could cause a perversion of morals on the same level?

People spoke against the Nazis then and slavey before, but the majority didn't. We're probably going through the exact same thing now with veganism. There's no moral argument for most people to continue consuming animal products, but here we are.