Chomsky hates Israel and loves Palestinian terrorists. Chomsky claims to be anti-Zionist, not anti-Jewish, but in the end it's hard to see what difference that makes. He encourages antisemitism whether he means to or not. For some secular Jews, this makes him a hero; for others, an anti-hero. It's tempting to consider his vast accomplishments in his field of linguistics, which I have no reason to think anyone disputes, but don't know firsthand. These accomplishments sometimes seem to give him a podium from which to encourage his fellow antisemites.
Another thing that's tempting is to dismiss him as simply a self-hating Jew who has come to hate most other Jews during a long life of contrarian behavior. Way too many demonstrably self-hating Jews have the same attitude, that Palestinians can do no wrong, and that Israelis have no rights.
Chomsky probably tries to complicate the issues; some of his followers and imitators don't even bother. I think for a lot of them (and I can't know which as I don't see the insides of their minds) the reality is, they are indifferent to the Zionist project -- they just hate Jews.