Part of the issue (and I feel this is on topic) is that a good part of the anti-Israel belief in the west is anti-colonialism. They see Israel as a western colonial project and are opposed to that aspect of it, not the Jewish aspect. if Israel was settled by western Christians with the backing of major western powers, a lot of people would be just as opposed to that nation. The fact that over time a lot of christians from the middle east moved there wouldn’t really be relevant.
I think thats part of the issue. Many people in the west aren’t anti-Israel because they are anti-Jewish, but they are anti-Israel because they are opposed to western colonialism.
But theres even more to it than that. Like Israel’s neighbors are constantly being defeated militarily which is humiliating for them. So its not just anti-Jewishness, or anti-colonialism, its also honor about being humiliated.
Also, and this is part of my thought process, is rejection of Israel (in the US) in a way a rejection of the fact that America doesn’t work for most people here anymore? Most people know politics is run by the oligarchs, and America is economically unsustainable for the bottom 80%. So being told to like America’s allies isn’t that appealing when you grew up in a nation that you knew didn’t represent you.
Plus some people support Israel and support the war against Hamas, they just don’t want Netanyahu and the Lukid party in charge while it happens. Theres lots of anti-Lukid protests within Israel among Jewish citizens who feel the war isn’t being waged properly.
My point is theres a wide range of reasons people would oppose Israel and/or its actions, and they all blur together (which I feel is on topic). So taking a half dozen reasons people might oppose Israel and trying to separate out the anti-semitism from the other reasons isn’t easy.