There was plenty of people who killed everybody who opposed them. And there is still plenty of such kind now. And actually there is not so much difference between them and Stalin. It is politic, bloody and dirty work, and there is not so much politicians with dry hands.
But genocide, killing a man only for his nation is over the edge even for sometimes so serious people like Russians. Without this insanity maybe there would be a good chance for Germany to win the war.
I was not trying to comprehend it but make a comparison between the older generations.
Hitler wanted to exterminate jews,gypsies,eastern europeans etc
Stalin killed everybody who opposed him.
Different motives but still same league of maniacs.