Nazis were worst of evil, and US needed USSR and viceversa.
Also no mater how groosome Katyn was- Auschwitz and Dachau were hell.
And at the end, USSR was the one force that defeated nazis and saved the world... including Poles and Poland from Nazi extermination...
More perished in the gulags than in all German (German not some mythical ‘Nazi’) concentration camps. You are spouting the post WWII propaganda line defending the betrayal of the Eastern European countries by their Western Allies, propaganda line that has served the Communists and the West equally well. The greater evil has been on the Left as it continues to this day. Thanks to FDR we had Kambodia Killing Fields and the Chinese Communist takeover. North Korean paradise? And you are telling us about some “worst of evil” of 70 years ago?
If the Soviets hadn't signed the Molotov-Ribbentrop Pact with Hitler, there would have been no WWII. Hitler was justifiably worried about a two front war. The Nazi invasion of France would have ended up with the Soviet occupation of Berlin without the Pact. Ultimately, the Soviets are indirectly responsible for deaths of 50m Europeans via that unholy pact.
And if the European powers hadn’t had their main forces tied up in Europe and overrun by Hitler, the Japanese invasion of East Asia would not have occurred. No Pearl Harbor, no 400,000 dead GI body count. Bottom line is that the Russians screwed Europe, Asia and millions of American servicemen big time. Asking for gratitude for helping put out the out-of-control fire that the Soviets started is a little excessive.