I read that he had an intense interest in Germany (as in acquiring knowledge) which would help to explain why his speeches worked so well on his intended audience.
I think of Hitler the same way I think of my ex-roommate, a completely helpless tyrant who relies on other people for any kind of authority. A year ago I was blindly doing whatever my roommate told me to do, it took me almost an entire year to realize that he was the biggest and most unappreciative liar I had met. Regardless of how bad my roommate was, he'd have brought a lot less of his brand of "bad" into the world if I hadn't helped him.