Clearly awful

I have a more pessimistic take : I don't know how many Germans actually regretted putting the Nazi Party in power. Maybe I'm misinterpreting your idea. A friend who lived in West Germany in the '80s told me that there were still many supporters of Nazism at the time, all in the closet.

This article suggests to me that the primary reason for the mass suicide was fear, not guilt, as the OP suggests.