I was sure that I read an editorial on this very topic somewhere, but I can't seem to find it.
I don't think this is a coincidence.
Nuremgard = Nuremberg
The Deathly Hallows symbol being seen as a sign of evil = The swastika--neither in actual fact a symbol of anything at all evil, but just seen as representitive of it.
The whole genocide theme, which I thought was very shocking indeed, with the Magic is Might statue of wizards a top of muggle bones.
The Death Eaters and the SS, although Rowling was originally going to name the Death Eaters the Knights of Walpurgis. Walpurgis Night, in Teutonic myth, was held on April 30 or the night before Beltane (May Day). Hitler committed suicide on April 30, 1945.
It was also believed that Hitler was part Jewish = Voldemort part muggle, Although Grindelwald was the contempory of Hitler, Voldemort could be equated to Himmler?
Hitler, not unlike Grindelwald, was partial to acient occult objects particularly 'Grail' items. He was said to have been in possesion of 'The Spear of Destiny until Walpurgis night. The Spear of Destiny and The Wand of Destiny, another similarity.
Personally, I think this is typical of one of the moral lessons that JKR placed within the pages of her books.
Edit: I knew I'd read something somewhere...and here it is! Just click on the 'Excerpt' link and open the folder!
Harry Potter and World WarII