Same reason the Kims are still in charge in North Korea: They don’t know any better.
You need to read some Russian history. Its very depressing (just like Russian literature...).
Russians and other former subjects for the Russian Empire were not treated any differently by the Soviets than they were by any Russian government before them. Some of them might have actually been treated somewhat better.
Add to that, the natural paranoia of a country that has been repeatedly invaded (including by us) and taken millions (yes, MILLIONS) of casualties, and, well, it makes sense.
Ray I’ve read lots of Russian history, LOTS of it. More then most Americans, trust me.You want a good one, read Harrison Salisbury’s “The 900 Days’’ dealing with the siege of Leningrad .Human life in Russia is worthless and one thing becomes apparent, Russians take a perverse pride in not taking responsibility for themselves. And yes they are roundly hated by Poles, Germans Chechzs, hell they even treat each other like something on the bottom of their shoe. And I agree Russian literature IS depressing... and pretentious too.