Blame George Lucas.
Before the seminal, triumphant and amazing Raiders of the Lost Ark premiered, Nazis were just a bunch of thick-headed brutes trying to take over the world. But the instant Belloq (Indy’s rascally archeological nemesis) opened up the Ark of the Covenant and unleashed a hot mess of face-melting-evil-smiting-ghost-lightning on the German troops gathered there, a new brand of Nazi enemy was born.
This new Nazi enemy was eager to seek out occultist artifacts on behalf of Der Fuhrer. This new Nazi enemy blended science and religion to wage a strange and mystical type of warfare against mankind. This new Nazi enemy saw beyond the meager dreams of Hitler and Arianism and genocide to true world domination through the summoning of ancient gods, demons of lore and dark, dark magic.
So, out with the complex and all-too-human historical Nazis, out with the stereotyped blonde lugs of 60’s and 70’s war films, and in with the enemy that’s worse than them all: the enemy that isn’t just devilish, or on the devil’s side–no, the one that can summon and control Old Scratch himself. Bwahaha!