Look at what Josh Block told Politico about what makes someone an anti-Semite:
As a progressive Democrat, I am convinced that on issues as important as the US-Israel alliance and the threat posed by Iran’s nuclear program, there is no room for uncivil discourse or name calling, like ‘Israel Firster or ‘Likudnik’, and policy or political rhetoric that is hostile to Israel, or suggests that Iran has no nuclear weapons program, has no place in the mainstream Democratic party discourse. I also believe that when it occurs, progressive institutions, have a responsibility not to tolerate such speech or arguments.
So according to Block, you are not allowed (unless you want to be found guilty of anti-Semitism) to use “policy rhetoric that is hostile to Israel” or — more amazingly — even to “suggest that Iran has no nuclear weapons program.” Those ideas are strictly off limits, declares the former AIPAC spokesman.