If you're actually interested in the geopolitics of this I suggest you just spend some time tonight reading about these relationships and their history.
I do think there are particular aspects about US support for Israel, outside of humanitarian concerns, that lead to people being more critical about US involvement in the conflict.
Well, yes. If someone doesn't like Jews (and many many many people do not), that is the only "particular aspect" they need. The one good thing about antisemitism is that it's been around for so long that it's pretty easy to spot, even when the bigots try to swap some of the terminology around.