Germans knew enough of what was going on. Claims of ignorance were lies.
Parents saw neighbors rounded up and had a pretty good idea what was happening. When their kids asked what happened the parents told them “nobody lived there, so don’t talk about it.”
I understand that they were silent in order to protect their kids. I don’t agree or approve of it, but I understand why.
Not all Germans were silent. There was several underground resistance movements against the Nazis and Hitler. The White Rose and Realm of the Black, Red and Gold were two notable ones. I had a great-great-great uncle who was in the latter. He was caught and sent to Dachau early on and killed by the SS. I think there may have been many people who would have stood up but they saw what the SS did to people like my uncle and shut up for their own survival.
Of course, there is also just the mass hysteria of being caught up in a movement. There was so much anti-Jewish propaganda for decades blaming them for all the woes that Weimar was facing, many silently (or openly) cheered.