It clearly, usually is.
If you were just critical of Isreali policies, you would say so. You're opposed to Israel's existence.
Maybe you're using the term because you think that it's a way of opposing a state founded on the basis of religion, or, in your words, an "ethnostate."
Okay, then use those terms and words.
I agree that we shouldn't have governments founded on the establishment of religion.
Still, there's no dearth of actual ethnostates and theologies in the world. Most Muslim states are so particular about the state religion that they segregate between Sunni and Shia states. I don't see you calling for the destruction of any of these other states, and the forced relocation of their people. Your focus on the one Jewish state in the world says a lot about you.
I don't know if many of you just know so little history that you think that the Jews were indigenous to Europe, and that they kicked out the indigenous people of Palestine. If that's the case, please get out of discussion. The Jews have been in that region for three thousand years.
Okay, maybe you just want Israel to have less land. Maybe you think that the Jews have a disproportionate amount of land. Okay, say that. "Anti-zionist" is the wrong word. Anti-zionism doesn't allow for a Jewish state of any kind in the region. So, you're saying that the Jews shouldn't have a home in their native land, it should be controlled by the Muslims, and the Jews should ether be expelled from the land, massacred, or treated as second class citizens. If you think that anything that Israel would be replaced with would be a liberal democracy with equal rights, you head is firmly planted in your ass.
So, if you proclaim yourself to be and anti-Zionist, I'm going to trust that you know what that means until you prove otherwise.
Until that may happen, the burden is on you to explain precisely how you reconcile your passionate support for the destruction of the only Jewish state in the world with not hating Jews.