Think about all of the crimes that Israel is accused of - apartheid, genocide, racism, infanticide, starvation as a weapon - all of it.
Now imagine what would happen if the people making these accusations thought of Jews as decent people - people who perhaps make mistakes but who do the best they can given the extraordinary circumstances they find themselves in.
Poof! All the accusations go away.
Because if you give Jews the same benefit of the doubt you give, say, Europeans - or Qataris, or Palestinians - you would consider that there are other factors in play, like Hamas' war strategy of maximizing civilian deaths (why are there extensive tunnels in Gaza but no bomb shelters again?) Or that the Jews live in a world where at any moment a Palestinian terrorist might pop up and start shooting or exploding a bomb belt. Or that Jews consider themselves a family, and even one death is one too many and something must be done to ensure it doesn't happen again.
There are explanations for every "proof" of Israeli evil that fit the facts much, much better than assumptions of "Jewish supremacy" or "anti-Palestinian racism." They aren't difficult to find - they are published in Zionist media daily.
But the "anti-Zionist" crowd doesn't want to think that Jews are decent human beings - and they don't want the world to consider that idea, either. So they not only ignore all counter-evidence, but they do everything they can to ridicule or ignore the many proofs that they have their facts wrong. And they want to make sure that you never compare Israeli actions with those of anyone else who have ever been in remotely similar circumstances.
If you think of Jews as normal human beings, everything looks different - and that's why "anti-Zionists" don't want you to think of Jews as human.
Anti-Zionism only works if Jews are cast as uniquely evil. Treat Jews as human, and the entire edifice collapses.