I think it was actually a good decision not to include or reference Nazis in the game. I'm guessing this was done in order to upset or offended anybody which I think is important to keep in mind. Secondly, although I don't condone anything the Nazis have done, I'm personally not a fan of the idea of putting them on the same level as demons and other monsters who you can kill in a video game without feeling bad about it.
They were never going to put Nazi's or Hitler outright in the game. However Brauner is an artist who looks Caucasian and paints with blood in the context of WWII, with a completely shaved head. I'd say it's safe to assume at least some inspiration from Hitler. Frankly I'm glad they didn't put Hitler in the game, the guy just doesn't seem threatening as an enemy in a video game. (not in Wolfenstein, not now)
They could, however, have put soldiers in the game (rather than recycled sprites) who could've been under the influence of chaos. Having a swastika on the wall of the nation of fools during the events of WWII could have been historically accurate. Placing soldiers (not specifically Nazi soldiers) in that stage who were under the influence of Dracula/ Brauner or influenced by the rising of chaos in general could have worked in context. This is not demonizing someone's belief system who follows the doctrine of Hitler, it's being somewhat historically accurate.
I'd also like to point out that games such as Wolfenstein 3d and Return to Castle Wolfenstein had similar themes, the Nazi's were the enemies of these games, it's a contextual plot device, that isn't taking digs at anyone's belief system. It's a representation of history. Hitler is a historical figure, as is Dracula and both have appeared in popular culture, comics being a prime example
https://www.mycomicshop.com/search?TID=275481 https://s-media-cache-ak0.pinimg.com/736x/91/ab/cb/91abcb98d796c3d0c7909da7f4ee565e.jpgCharacters such as these as well as their associations, give historical context to a plot or situation. Nobody is saying if soldiers were in the game they had to be killed or vanquished inhumanely, they could have been zombie soldiers or the like. Dracula's influence would have been enough of a logistical and rational reason for their "evil".