Many highly rational people get sucked into making decisions merely on math, ignoring the ethical aspects. Ironically, on HN that decision making process is often mirrored and so discussions tend to fall into the same trap.
(Except that liberating Russians would have gone a whole lot worse. You would end up liberating half of Eastern Europe, and probably the whole Germany, along the way.)
In Warsaw, after the war, when it fell under Soviet occupation, a popular opposition slogan was Truman, Truman, spuść ta bania, bo to nie do wytrzymania which roughly translates to Truman, Truman, drop the nukes, because we can't take this any more. Irradiated ruins were preferable to communism.
I don't think condemning millions the horrors of war is worth saving them from a shabby existence.