Tankies like to talk about how Marx, Lenin, and Trotsky were Jewish or had some Jewish heritage to support their crackpot idea that Communism has always been amazing for Jews. Their understanding of those figures' Judaism is incredibly surface-level, however, because they fail to understand that the Jewish partial-architects of Communism were deeply self-hating, and I don't mean anti-Israel, I mean antisemitic.
Karl Marx effectively renounced Judaism altogether, married a gentile woman (on whom, I might add, he dumped every bit of domestic labor while he drank and navel-gazed), and wrote an incredibly antisemitic essay called "On the Jewish Question" where he rebutted someone else's antisemitism by saying that "practical Judaism" was "huckstering and money," that "the Christians have become Jews," and that humankind needed to be emancipated from this so-called "practical Judaism."
Lenin, who had a single Jewish grandmother, insisted that Jews needed to assimilate in order to have a utopian Communist society and that Jewish persecution in Eastern Europe was their own fault for remaining a separate community. As far as I know, he did not routinely interact with Jews.
Trotsky is arguably the only Jewish figure in early Communism to have considered antisemitism an undeserved and extrinsic evil, and even he considered it largely a Tsarist evil. He changed his name from Bronstein to a "revolutionary" one. At one point, he said that he was a Bolshevik, not a Jew, and he even considered rejecting a position in the Communist government because he thought that there shouldn't be too many Jews in high positions. (The "Judeo-Bolshevik" stereotype was based on him, not on an actual environment friendly to Jews.) The party also turned on him when he started speaking out against Stalin, and he was eventually killed with an ice pick to the head while in exile.
Your precious Marxism has never, ever been built around fighting antisemitism, nor has it been a safe place for Jews. You only have to look up the Doctors' Plot, "rootless cosmopolitans," and banning of Hebrew and Jewish culture to know that.