I didn't claim that "antisemitism is a 19th century innovation", I claimed that Anti-Semitism in the sense of "against the Semitic race", as I described in my previous comment, is a 19th century invention. A distinction I made to describe a specific part of the Nazi world view.
This is not "weird thing", it's a mainstream view that I got from mainstream Jewish authors on the history of Jews. But hey, maybe those are also weird *shrug*
And your extremely condescending attitude is not appreciated.