Zionism is no more nor less than the self-determination of the Jewish people — as a people, and not just as adherents of the Jewish religion. Jews are in fact the only people – asa people — for whom Israel (ancient Judea and Samaria) was ever their national homeland. Those who deny Zionism thus deny Jewish peoplehood and the fundamental right of Jews to live as a people in their own ancestral homeland, Israel.
Unique in the world, Jews are both a people and adherents of a religion. Intrinsic to and inseparable from the religion of Judaism is the land of Israel; more specifically, the centrality of and longing for Jerusalem and its Temple. Deny that centrality and you rip the heart and soul out of Judaism. Those who deny the right of the Jews to Israel and Jerusalem deny the right of the Jews to their own religion.