Fascists get away with conflating Judaism and Zionism because they don't teach that Zionism has absolutely nothing to do with Judaism, and actually goes against a lot of their values. It's actually been around for quite awhile; you know the crusades, when they went around killing a bunch of civilians to set up settlements? Those were Christian Zionists.

That's why it's anti-semitic to conflate the two. One is a religion and the other is a fascist genocidal colonialist movement. So next time you see some german lady shouting down a holocaust survivor for calling out Israeli apartheid (yes, this literally happened, and it was the Jewish guy who got punished) you'll see it for what it is. It's not complicated, it's a clear cut case of modern day nazism.