When we look at WW2 and the motivations people had to fight for Fascism, the main issue is to avoid Presentism. Today's "acknowledged" moral compass has largely been shaped up by WW2 and the lessons humanity learnt from it.

Back in the days, antisemitism and nationalism, especially in Germany, were extremely hardcore.

Reluctant people were quite scarce, because if you were a young (18-24) German, you probably grew up spoonfed with Stab-in-the-Back propaganda, since your parents or grand parents were very likely to be people who fought in WW1 or did not understand why Germany lost in 1918.

You did have Pacifist movements in interwar Germany, especially amongst the artistic & student communities or republican parties, but most of them quickly lost steam through the 30's with the drastic political & cultural suppression organised by the Nazis.

If you or me went back in time, it is very likely that we would find many people to be "evil" or downright insane, even in allied countries for that matter.

The simple, but sad reality is that most people back then were "okay" with the idea of waging a war of aggression for revenge against the victors of WW1, territorial gains etc.. Even if they did not care/agree/comply with the racial component of the war (which would, again, be against the norm back then.)