Those were options on the table though. There was no magic kingdom with ponies around, and both monarchists and right-wingers were quite a match, if not beyond Stalin's atrocities during Civil War (at their scales).
Nope, that didn't happen even by most suspect Western estimates. All "purges" and "holodomors" were pre-war, check your facts (and consider that you are, indeed, brainwashed into believing that).Also, Stalin murder millions of his people after WW2.
He wasn't sadistically cruel though; he just wasn't particularly merciful, and didn't consider human life to be intrinsically valuable (like many of his contemporaries).The war was over, the threat was done. There was no need to be as sadistically cruel as he was. The fact that you are saying that all of this was acceptable for progress is disgusting.