Antisemitism was (still fundamentally is) systemic in Europe because of the formation of capitalist nation-states.
The nation-state seeks to establish a difference between people based on borders, in order to prevent solidarity between workers who share a way of life, and even sometimes a language, customs, a religion, despite being born across borders. It will use anything to both unite the people inside its border and antigonize the ones beyond, especially racism.
Jewish people, as a disaspora, as well as any nomadic people like the Romani, fundamentally challenge the nation state because they are united beyond borders. Therefore they became prime targets for persecution. People literally said shit like "they can't be trusted because they have no country, no state"
So the origin of anti-Semitism is that Europeans though that the Jews being stateless was bad. So when the Europeans are trying to "give" Jewish people a state, they are in fact trying to "fix" them. Zionism is an attempt by the anti-semites to make Jewish people conform to their worldview. Zionism wants to get rid of the cosmopolitans, it's a project of sending the Jews "back home" so they leave Europe and stop being a threat to the oppressive capitalist regimes. Zionism wants to erase what makes Jewish people special and progressive. Zionism is the death of Jewishness.