Actually, I think you get a lot of considered criticism of Israeli government policy on MN from people who believe that a) Israel has every right to exist, b) that it had every right to defend itself after the October 7th atrocities and c) that Hamas is a despicable terrorist organisation that should release the remaining hostages right now BUT ALSO feel that the Israeli government's response has been horribly disproportionate, that Israel's ongoing actions in Gaza are totally unacceptable, and that the suffering of innovation Palestinian civilians needs to stop.
Absolutely you get some vicious antisemitic comments on some threads, and I have reported these when I have encountered them. Such comments are utterly abhorrent and they should be reported and deleted in the same way that every other racist comment on this site should be reported and deleted. There should be no place for those spewing their hatred of Jewish people here on MN, or indeed, anywhere else in any civilised society.
But legitimate criticism of the Israeli government is not inherently antisemitic, in the same way that criticism of the UK's immigration policy is not inherently racist. It tips into antisemitism/racism when people start trying up stir up hate or spread claims that aren't true.