I read somewhere, that the Neanders were actually the more intelligent, peaceful human race... thats why they were wiped out by the more aggressive, yet dumber homo sapiens.
And yeah, its a fiction, 'white' supremacy has little meaning here. And even if they are 'purist', what exactly wrong with that?
Instead of Hitler, being the King, my theory is that a future Neander from a different timeline, where they flourished instead of the Homo Sapiens were sent back, and now its a battle who wins the future... fought in the past, supported by agents from the future (both timelines), to make it more fair.