The Soviets needed to keep going to Berlin in order to beat the enemy that had attacked them. It was necessary for self-defense. So did the European members of the Western Allies. America got involved because that's what America does, and it's not super obvious that America's involvement was a good or necessary thing.

There's a difference between a violent revolution in your own country as a means of self-liberation and inflicting military destruction on another country because you think you have the right or prerogative to do so. Socialism is also a humanitarian ideology. How do you reconcile socialism with causing death and misery through an unnecessary war?