There are different things here that you are glossing over and conflating.

Yes, there is a moral right and necessity for self-determination and self-defense for the Jews after the Holocaust. But there is no necessity or justification for that to happen in Palestine, especially when this means displacing and slaughtering the Palestinians who have lived there for quite a few centuries. And indeed Palestinians do have a moral right of self-determination and self-defense as well. So the essence of Zionism, which is the idea of taking over Palestine for a Jewish state, is deeply immoral because of that. And this immorality doesn't simply disappear because of the wrongs that were done to the Jews by non-Palestinians. And because of that, anti-Zionism is a moral imperative, because it aims to correct an immorality. Whereas antisemitism is something completely different.

> Anti-Zionism is antisemitic because it declares that no, it is preferable for Jews to continue to face the Holocaust and other attempts at their genocide than to concede their right to self defense as a people.

Which means that you think the only possible way to avoid a genocide of Jews and for Jews to defend themselves is to settle in Palestine? Nothing else would have done? Given that there were quite a few wars around the establishment of Israel which could have very well wiped Israel off the map that is quite a bold statement.

I rather think this idea of self-defense and self-determination of the Jewish people being only possible in Israel/Palestine is a religiously derived idea, nothing that has any basis in political and military facts or morals. It was just a "wouldn't it be nice to do this in Gods Promised Land?" kind of thing, current inhabitants be damned...