I agree with your 3rd point: the people that disagreed knew that the things that were being done were inherently wrong!
It was wrong to them. To Hitler it was ok and necessary. To other Germans the Jews were getting what they deserved (some people still share this view).
Going back to abortion, today it is considered acceptable, in American Society, to have an abortion regardless of the reason. 100 years from now American Society may view this period as a giant black eye in American History. 150 years ago a great portion of American Society thought Slavery was ok.