I am not talking about WWII at all because it is irrelevant to the discussion at hand

I brought up WWII because the peak of the Gulag system was starting on 1936, and by Stalin's death in the mid-1950s it had essentially disappeared, it was a system implemented during a time of extreme necessity due to dekulakization, maintained during WW2 and the Nazi hysteria of the late 1930s after the assassination of Kirov, and dismantled after Nazism had been eliminated from Europe.

really quite racist

The USSR was patently the least racist nation in Europe. While in my homeland of Spain education in Basque and Catalan was forbidden, the Soviet Union for the first time in history guaranteed the citizens of all the republics an education in the official language of their choice, leading for the first time to universal education in Ukrainian, Kazakh, Belarusian, or even minor languages such as Mari for those who spoke it and desired to be educated in such languages. In France, up to 1993, there were no public schools teaching children in Occitan language, and even now I don't think there's even one. Fuck, the "Union of Socialist Soviet Republics" doesn't even have a toponym or an ethnicity in its name, how many countries can claim the same?!

evil and oppressive

Look. I'm a Spaniard. In 1936, we had a fascist coup which resulted in a civil war between fascists and anti-fascists. The policy of the western world was to do nothing and to leave the war to itself while the Nazis and the Italian Fascists bombed the fuck out of my country's partisans (ever heard of Picasso's Gernika?). The only nation in the planet to help the antifascist struggle was the Soviet Union, which is the only source of Spanish antifascists of weapons, planes, tanks and military training against the fascists. It's crazy to tell me that the only nation that helped the fight against fascism in my homeland was "evil and oppressive". Your grandpa, a Jewish man, would have been murdered if it weren't for the Soviets. The very fact that you're here is because of the 27 million lives that the Soviet Union sacrificed in order to save Europe from Nazism.