George W. Bush was called a racist over and over again for his attempt to oust the existing powers in those countries, and replace them with powers more to Western liking.
What we've already clearly seen is that it's possible to go far beyond harsh criticism of a nation while still believing that it should exist. It's not hard for me to criticize Iraq and Afghanistan for their treatment of women, and homosexuals, and political dissidents, and, in the case of Iraq, the constant oppression and regular murder of the Kurds, and call for reform, without saying that the nation has no right to exist.
So, if you're a self-identfied anti-zionist, and chanting from "The river to the sea!" You've gotta scout yourself.
The only way that you come to the point of not simply criticizing Israeli policy, and calling for a regime change, but calling for her destruction, is if you have a particular dislike for Jews.
Even if I were to call for the complete destruction of a nation like Iraq, which I never have, and I got what a was calling for, the Iraqi Muslims would still have other Muslim countries to go to. The Jews have one state in their native land, and you're singling them out to lose even that.
Take a moment to examine your own mind. What crime could a nation commit for you to call not for a regime change, not for a policy change, but for its complete destruction?