When you defend Whoopi by saying "Why agree with Hitler?" I think you're conflating two propositions:

A. Jews are a race.

B. The Holocaust was about race.

B can be true without A being true. It's one thing to say "Hitler was wrong; Jews aren't a race," but that doesn't change the fact that the Holocaust was *about* race - it was motivated by Nazi racial theories, whether Jews are actually a race or not.

Or at least, it was about race as much as the South African Apartheid or Jim Crow were about race. Race is a construct, but these things were still "about race."