Yes: as far as the German churches, it was a relative handful of people like Dietrich Bonhoeffer who opposed Hitler openly and - to their shame (like the "ordinary" Germans) - Protestant and Roman Catholic clergy/leadership seemed to find it in their interests to either remain silent or even back Hitler.
I think the reason people agree on morality to the extent that they do is that a sense of right and wrong is imprinted in our nature. We are good at ignoring it or making it situational, though. For example, many who commit adultery find all kinds of ways to assuage their consciences, though if it were the same person's spouse who did the cheating, they would be incensed and unforgiving...telling anyone who would listen how their former partner did them "wrong."
Like Sartre, you are at least willing to bite the philosophical bullet. The difference between him and Dostoevsky is that D saw that phrase not as a statement of human freedom, but a warning of unbridled terror.
Your comment deserves a better response than is possible in this forum. I will respectfully point you to Alvin Plantinga's book: "God, Freedom and Evil" as one of the best ways to address this issue.