I take issue with every sentence you wrote. "Highly educated"? I don't think so. "Some of the authors" - you mean Nietzsche, I guess. It seems likely he didn't read Nietzsche's books, but just the bits quoted in (anti-semitic) newspapers. Check out Chamberlain and Schönerer. The first thing you notice is the strong Nazi-type flavour of their thoughts. Wagner and Luther are notorious for their extreme anti-semitism. That first wiki-sentence comes to "He read the paper". My understanding is, on the street corners and cafes of Vienna in those days were a dozen different half-nutty political groups, and Hitler took a bit from every one of them. The stuff was in the air, if you stopped to breathe it in.

https://en.wikipedia.org/wiki/Houston_Stewart_Chamberlain

https://en.wikipedia.org/wiki/Georg_Ritter_von_Sch%C3%B6nere...