People act like the USSR were some kind of saviors for the Jewish people as if the Germans/Hitler/Nazis held some kind of monopoly on antisemitism, which is comically false. The Russians have hated their Jews for literal centuries. They hated us before the USSR during the time of the Czars (literally just google the word “Pogrom”), during the time of the USSR when the culturally Christian-style of atheism was set in place and Judaism was classified as “Zionism” (Different from the racist style of Zionism that the Israeli apartheid state perpetrates) and therefore an “Ideology” that was “detrimental” to the Communist state. Jews became second-class citizens in the Soviet state where we were subjected to constant surveillance, kidnappings, interrogations, torture, and the inability to leave. And then after the collapse of the USSR and into the modern day.
Stalin was more than willing to work with Hitler and the Nazis despite the fact that Fascism and Communism are the antithesis of each other as they both had imperialist desires and intentions. This was proven by the signing of the Molotov-Ribbentrop pact, where the USSR pretty much gave the Nazis their blessings to invade Poland (a joint invasion where the USSR would be given the eastern portions of the Polish state with assistance from the Wehrmacht) and the USSR would be allowed to invade the Baltic states, Finland, etc. Stalin was fully aware of Hitler’s antisemitism (how could you not be?) and massacres against the Jewish population of Poland began almost immediately as soon as the German invasion began. The Nazis never would have invaded Poland without Stalin’s blessing so as to avoid another two-front war situation that inevitably caused Germany to lose WW1. Also lets not forget the conferences between the NKVD (Soviet secret police) and the Gestapo (Nazi secret police) where the two sides shared many strategies and tactics for dealing with the deportations and murders of Jews, polish nationals, and any other kind of dissenters.
Say what you will about the minor improvements that Soviet Jews had
under Stalin such as migrations from the Pale into the cities, Stalin
delivered Poland and its Jews right into Hitlers hands. The only reason Stalin and the USSR went to war with Germany is the obvious fact that Germany broke the pact and invaded the USSR in what we now know as Operation Barbarossa.
tl;dr the Soviets were never allies of the Jewish people, the USSR was more than willing to cooperate and collaborate with the Nazis in the murder of Jews and it only stopped when Hitler broke the pact that allowed him free reign in eastern Europe.