I think you both seem to have forgotten the violence and intimidation that the Nazi's inflicted on political opponents during their rise to power. The first concentration camps housed political opponents of all kinds, the Nazi's regularly attacked in the streets the leftists opposing them, and they engaged in all sorts of propaganda and false flag operations. In short many of the people were first duped and/or intimidated, but others opposed the Nazi regime from the beginning and were slaughtered for it. And by the way, Hitler's generals did try to kill him.
Finally, democracy doesn't guarantee justice in all moments of history, but it does so over longer periods of time when it becomes the culture of a society. The alternative is to have some band of elites or a dictator controlling a country, with the inevitable corruption caused by power. So yes, on average over time, government by will of the people is better than government foisted on the people by politicians ramming their world view down the throats of the citizens. This is something I fear a certain political party in the US understands less and less...
Oh, yes, that is correct also. They did shut-down or kill anyone who opposed them, so it's a mix of both.
My point is that is that there were cultural, moral, and even scientific ideas that allowed the Nazis enough power and momentum to get there and get away with it. And... (this is super important), the Nazis and their supporters believed they were doing a good thing (within their own moral belief system and worldview).
I think some people have the impression that a crazy person, or a few, got into power and then forced an evil plan into action while the citizens helplessly looked on.
I disagree about democracy though... in that I guess it's better than a bad dictator, but there have been enough bad cultures throughout history that a bad democracy could be just as evil. Most western democracies haven't been true democracy in that they are often grounded in some kind of charter, or in the case of the USA, the Constitution, which has some amount of power over the people... or at least really slows down just flowing with the culture.
It is ***supposed*** to be really hard to modify the Constitution, though yes, the democracy can do so. I suppose that is somewhat like the 'long-term' you're talking about. But, even the USA is in trouble now with judicial activism and postmodern reader-responsive interpretation. And, a pure democracy could change in major ways nearly overnight. That's quite dangerous.