As stated, he did not only kill Russians. I myself lost four relatives to their brutality, and various others were tortured and then released by the Soviets. What was the crime, you may ask? The fact they were German.
Here, people, is one of the worst mistakes to be made by any who workship Stalin and the like. Stalin, like Hitler, like Videla in Argentina, Pinochet in Chile, and so many other dictators made what Stalin called: political cleaning.

What is political cleaning? It is the authoritarian attitude to eliminate, for once and all, all those people, religious autorities, media, political parties and thinkers that can make any kind of "opposition" to the ruling coup. All the dictatorships had different ideologies, yet they supported one idea in common; to not to have any kind of opposition, they had to do something. They didn't care how many censorship, manipulation, propaganda, State Terrorism they managed to use, they would say if 2+2 = 5 if they say so... what they didn't know that if somebody else thought that 2 + 2 = 4, and that person wouldn't said that... he would be free and knowing there is something else of what they say. Statal terrorism was conducted by dictatorships to last longer.

It's something else than: If you don't follow us, then we send you to Gulags. Its the failure of knowing that there are other points of view, everyone can learn from those others points of view, but yet they are too busy trying to prove their point.

Sure, Stalin was evil, but to compare him to Hitler is ignorance. Thankless ignorance.
They both were dictators, harrased with their enemies sending them to concentration camps. Enough said.

He killed a massive number of Poles, for example.
There was a file, I think it was called The X Paragraph or something, which stated that there was xenophobia between Russians (Of Commie Russia) and the rest of the countries that were part of the USSR.