Yeah, Rowling’s Death Eaters can very much be read as a drop-in replacement for white supremacists. Even the name “Death Eaters” is derived from a particularly nasty term the early Nazis sometimes used to describe themselves, so she did some research. Also the fact that their leader is someone they’d normally persecute as a mudblood tells of their complex and twisted worldview.
The Believer is another illustration of some of the crazy contradictions that can be found in white supremacy, and it’s based (loosely) on a true story.