He was a pretty bad guy, but I find it hilarious how everyone flip-flops on him.
When people want to compare conservatives to him, they'll make him seem like some big Christian Fo Fun Allowed right-winger/witch-hunting fundie because he valued "wholesomeness". When people want to compare metalheads, pagans and horror/science fiction/fantasy fans to him, they'll bring up his interest in the occult and Norse mythology, his well-documented love for King Kong, Frankenstein, Metropolis, Snow White and Flash Gordon and paint him as basically being an angry Goth kid.
Some will paint him as a meathead anti-intellectual because he burned some books, didn't like Modern Art, implemented exercise programs and went after Jewish philosophers (Jews being killed...in a mass genocide of Jews? How unusual...), then others will paint him as weak, effeminate nerd who was into art and painting, classical music, opera and theater, and argue he's a reason we should bully and ostracize anyone who isn't a 100% masculine captain of their high school football team.
The dude has just become an all-purpose villain for everyone, no matter how contradictory the examples. Any value to be 'learned' from trying to avoid being like Hitler has pretty much been ruined by modern culture, and the only thing there ever was to be learned was pretty much "Don't genocide people". I think that's a lesson most average everyday people aren't ever going to have to learn unless they somehow get access to nukes.