1) Was Josef Stalin anything other that a bloodthirsty dictator?
2) Did we ally ourselves with him for any reason other that that he was anti-National Socialist?
If you're going to object to 'coddling' anti-communist dictators, I'd expect (as a matter of intellectual honesty) that you'd object to outright alliance with anti-National Socialist dictators.
Is it your contention that we should not have allied ourselves with the Soviet Union in order to defeat Hitler?