@JTT,
Other factors JTT leaves out are Stalin's competition with Hitler to seize power in Germany itself. For many Germans the principal attraction of Hitler was that he was opposed to the German Communist Party, then a very formidable force that took its marching orders from Moscow.
Then there was the Nazi Soviet non-aggression pact under which the USSR seized the Baltic Republics (transporting about 1/3rd of their populations to Siberia and repalcing them with Russians) and mutual invasion of Poland soon afterward. The USSR was from the start Hitler's principal enemy both from political considerations and his twisted ethnic views and ambitions for the physical expansion of the German Reich.
We had as much reason to oppose the USSR as Hitler in WWII but President Roosevelt found it convenient to treat them as newly reformed and heroic allies. Churchill was always skeptical of this, and history has largely demonstrated he was right..
The Soviets didn't do "more than their share" of the fighting in WWII. Instead they did exactly what they, their policy and their implaccable foe in Germany required. While the 20 million civilian and military casualties that occurred were truly horrible, they were of the same order of magnitude of the deaths Stalin had already imposed on Ukhranians, Lithuanians, Latvians, Estonians and Poles - as well as Russian dissenters - even before the fighting started.
A case can be made that our bombing of cities in Europe and Japan was excessive. However that also implies that Roosevelt's demand for unconditional surrender was also wrong and that a political accomodation with the German and Japanese Governments was preferable to what we did. How would you deal with all that?
I recognize that these sometimes perverse complications of the real world threaten the purity of your ever self-righteous moral indignation. so perhaps you might just ignore them.