Legitimate criticism is about specific actions or behaviors. You could even say that you are opposed to certain laws, like the right of return.
Saying that a nation should just not exist, regardless of how they behave or what laws they have betrays a deeper irrational hatred. Especially if there’s only one state that must not exist, while there are many countries with laws you would disagree with.
Are you against the existence of South Africa? Or were you against the existence of some laws in South Africa?
It also isn’t racist to be against the existence of states in general and believe in a world without borders. But to say that Ukraine has a right to exist, Ireland has a right to exist, Palestine has a right to exist, Greenland has a right to exist - only Israel does not have a right to exist is antisemitic.
> Denying the Jewish people their right to self-determination, e.g., by claiming that the existence of a State of Israel is a racist endeavor.
> Drawing comparisons of contemporary Israeli policy to that of the Nazis.
[1] https://holocaustremembrance.com/resources/working-definitio...