That's because....
http://en.wikipedia.org/wiki/Holodomor
If you've ever read about it, you know HOW super fucked up it was. Lots of cases of cannibalism, parents were literally eating their children.
I have no idea why Stalin isn't considered universally as bad or worse than Hitler (at least in general public perception). Most people know Stalin was a mass murdering tyrant, but I feel like Hitler is just talked about way more than Stalin when it comes to "being evil". They're on the same level of genocide. Pol Pot also
When I saw Bill Burr live he did over an hour of all new material
This was a topic he went over. Of course he turned it into hilarity.
"why is it every time someone does something fucked up they're like Hitler?
I bet Stalin is burning in hell thinking, how many did he kill? How is he in the Hall Of Fame? Here I am putting up crazy numbers nobody cares about. If you think about it Stalin is the Satchel Paige of mass murder"
Something to that effect. I was the only person in the room who got the Paige reference. I screamed out dying laughing. I got to talk to him afterwards he's real real good people man