The Russians were Poland’s enemies twice, during the same waR! First, they invaded with the Germans in September 1939. Had they not, the vaunted Blitzkreig would have slowed significantly. (The result would unlikely have changed, but certainly would have taken much longer.)
Then, when the Russians had the upperhand on the Eastern Front and were rolling the Germans back the Poles assisted with the Warsaw uprising in August and September of 1944. But the Russians, deliberately halted their movements in Poland while the Germans brutally put down the uprising. This calculated move should never be forgotten.
That’s right; Stalin didn’t want an independent pro-Western government in power when the Soviets reached Warsaw (that is why the Soviets executed Polish officers and such in the first invasion), so they let the Germans crush them first.
In the end, Britain and France went to war for Poland’s independence and ended up without it; Churchill was furious. All those lives wasted for nothing, and they both ended up with very weakened empires.
The other “Holocaust” nobody bothers to mention is the 100,000+ Poles killed by ethnic Ukrainians during the war, in the Volhynia Region.