I actually do think there is something to the whole "Jewish race" theory, atleast initially. There have been a lot of studies on DNA heritage. But what's funny is that while the modern stereotype is that most Jewish people have black/brown hair, prior to the 20th century, red hair was a popular negative Jewish trait, because of Judas.
I think Hitler's acts were racist (and catastrophically evil), because he specifically believed that his "Aryan race" was superior. While Judaism is a religion, he was lumping all Jewish people together as one race of people.