There is a far leap between "interested in Palestinian issues" and "anti-Zionism."
Also, you're obviously misrepresenting his claims. He says the people who rage against Israel are supporting all of the things that the Palestinians represent: Rampant anti-Semitism, genocidal ideation, glorification of Jihad, murder of Jews, etc. And that is true. You cannot support a movement without supporting, or being accepting of the outcome of that movement.
Well, he claims that the
entire Palestinian cause is a "sham" (his words) and that it's being used as a pawn for a giant Muslim conspiracy that wants to destroy Israel and turn the Middle East into a caliphate, and that the entire Western leftist support-base for the Palestinians has been roped into this conspiracy, knowingly or not. That's very different from a straightforward critique of anti-Zionism and antisemitism.
The JIDF is nuts, but notice they labeled him anti-semitic scum because he disagreed with settlements. But I know, he's a pro-Israel "shill." BTW, I looked up shill in the dictionary, and that does not describe him at all.
I think it's fair to call someone who believes that Israel has an indisputable right to exist but that Palestinians do not a shill, breh. I didn't mean it in the conspiratorial sense of the term, so if you want, I'll just be more precise and call him an extremist, but regardless, it doesn't get much more black and white or extreme than that imo.
He disagreed with settlements because he identified the settlements he was discussing as religious in inspiration (which many of them are) and he hates religion and doesn't think it belongs in political claims, not because of anything intrinsic to Jewish people or specific to Judaism, so even if one disagrees, I don't think his view can legitimately be called antisemitic.