I think that Nazi regime was unique in world history in that it unlike any other regime before and after had two faces: it externally pretended to be a left-center force, a left-centrist socialist pro-workers, progressive, anti-monarchist, anti-religious, pro-women rights, pro-animal rights, anti-capitalist, anti-monarchist party. But in reality it turned out that Nazism was actually far more right than any monarchists, Russian "black-hundreds" and conservatives were before. It was hiding its ultra-right face for a while to achieve popular support.
This duality led to many mistakes by individuals and politicians who made deals with Nazi party and Nazi Germany. German Cristians thought they are dealing with a centrist patriotic party when voting for enabling act. Vatican thought Hitler is quite like Mussolini: a moderately conservative centrist. Stalin thought he was dealing with a left-center party of small bourgeoisie. Ethnic minorities also thought Nazis are pro-national self-determination and cultural autonomy.
Many Jews saw that Nazis for a first time in 2000 years allowed Jews to have their own police, ambulance service, postal service, orphanages, and even telephone stations. They did not knew the orphanages and hospitals were designed to quickly separate those unable to work. Nobody could imagine Nazis will kill people in new shining uniforms they just designed for Jewish police (no other regime gives a forage cap with a badge to a condemned enemy).
Many Russians and Ukrainians believed Germans will build a moderate form of Socialism without collectivization and other excesses of Soviet Union.
Many Germans believed that Nazis really protect animal rights for ethical reasons, not just to make a ban on Jewish meat.
In reality it turned out that even conservative clergymen looked like Bolshevicks compared to Nazis.