“If you support Palestina, you are against Israel. And you can’t be against Israel, because then you are an anti-semite and that means you support Hitler.”
It’s mainly prevelant in western countries that historically support Israel. I do think a big part of that is some historical shame/feeling the Jewish people are owed something, given the genocide they had to endure in WW2. And of course a touch of geopolitics. And right wing politicians using Israel as a way to position themselves (I guess they hate Muslims more than Jews?).