I think a big part of it, here in the US, is besides all the post WW2 sentiment, a lot of folks here in the bible belt literally think they are God's chosen people, and so whatever they do is right by God, no matter how terrible. I recently showed up for jury duty and was speaking to a lady there about her son who had joined the Marine Corps. and thought he might get deployed, and she said, I shit you not, "At least he'll be fighting for God's people".
I've seen antisemitism. I've been in online communities that slowly devolved into rat caricatures and conspiracy theories about how Jews are out to destroy the world. So I know that modern antisemitism persists and is a thing to watch out for. But it's not antisemitic to admit that Zionist Israel is butchering innocent people because they want to claim all of Palestine for themselves, and that the west is too weak willed to do anything about it for fear of being called antisemitic, or going against "God's chosen people". That's not antisemitism, it's an objective, observable fact.
The even bigger issue is the Bible Belt is those moron’s reading of Revelation, which has them thinking Israel has to control Jerusalem for the rapture to happen.