The Nazis knew perfectly well that what they were doing was wrong and if they lost the war they would be held to account. Another reason so many at the top committed suicide - they knew what fate awaited them for their evil crimes.
Quite. The little pee-pants paperhanger shot his pregnant airhead plaything, then shot himself, and Goebbels did the same thing with his wife and family and himself the next day. Goering took poison in his cell sometime during his trial — it was slipped to him by a sympathizer, or some German employee at the facility. Himmler was captured by the Red Army, his interrogators didn’t quite believe his phony ID papers, and finally he got tired of the questioning, said, “I am Heinrich Himmler,” and bit the capsule to kill himself. The mayor of a town near one of the death camps and his wife, were forced with others to tour the camps with their dead, dying, and starving inmates, and he and his wife killed themselves when they returned home. And the Red Army occupation was so horrible that many ordinary Germans killed themselves rather than live under it. I’m reminded of the line from an old Genesis song, “death is easy as a substitute for pride.”