From Anti-Israel and Anti-Zionist Campaigns - ADL

While criticism of Israeli policies and actions is part of that discourse, certain forms of anti-Israel rhetoric and activism delegitimize Israel and its existence, and are antisemitic when they vilify and negate Zionism – the movement for Jewish self-determination and statehood – or utilize anti-Jewish tropes or hold all Jews responsible for Israel’s actions.

1. They try to portray zionism this way in order to legitimize settler colonialism, and equate anti-zionism with antisemitism. Historically this chance was lost well over a century ago. See quote above from Jewish Voice for Peace and their site for details.
2. Check out the Ben Gurion and the critic he got from Bundists. If you like videos, this one is pretty informative:
   The History of "Socialist" Zionism | Leftist Zionists did the Nakba & founded Israel
3. If you like text you could take a look at:
   The Neglected History of the State of Israel - The Revisionist faction of Zionism that ended up triumphing adhered to literal fascist doctrines and traditions.