By the time the "death camps" started, Nazism’s takeover of Germany’s society was complete; peer pressure was now doing the work that initially thugs had to do. Yes, there was a resistance because there will always be people who disagree with whomever is in power, but those people where
acting against the norm. Only with Germany losing the war were they rehabilitated in the eyes of Germany society at large, and initially with some grudging resistance here and there.
This is why posting about how “Nazism is objectively immoral, m’kay?" misses the point and can be counterproductive. The whole reason that fascism is a continual spectre is that, it turns out, by appealing to people’s base instincts and cracking heads, a malevolent political form can completely sidestep morality and institute the society it wants to see.