Respectable mainstream conservatives would rather have the nazis running Germany than risking mild social democratic reforms.
Big industrialists funded the Nazis like crazy
Centrists believed the Nazis would keep their promises of they supported them
The fucking SPD invited the Freikorps to crush the proletarian revolution in 1919. They then went on to have their heads up their arses and spent their energy fighting the KPD instead of the Nazis, right up until the takeover.
The police and the courts were extremely friendly to the Nazis and let them get away with almost anything as long as they staved off the reds.
In short, Germany fell to fascism because the German bourgeoisie wanted it to fall.
This is of course an unacceptable conclusion to liberals so instead they make up bullshit about voting, like that ever changed anything.
I've done a bunch of research into the lead up to WWII and the evidence is clear that the UK was intentionally stoking tensions between Germany and the Soviets (a good summary from Counterpunch). What I still haven't figured out, though, is why Poland was the line in the sand for the policy of appeasement. If the UK wanted an armed conflict between Germany and the USSR, why be so passive on Austria and Czechoslovakia only to flip when Poland is threatened, when a partially annexed Poland would have been the gateway for the Eastern war that UK seemed to desire?