Describing ethnicity based deportations and gulags as """"prisons"""" is one hell of a stretch.
This also neglects the amount of emancipatory legislation that Stalin repealed during his reign. Like recriminalizing homosexuality, abolishing the local language initiatives and instead pushing for his russification of the country (compare the ethnic make up of the Soviet leadership in 1921 and 1939)
The Soviet Union had its successes and it had its abject failures. Acknowledging them doesnt make you a librul or a revisionist.
My main contact with ml circles were a reading group some years back and hexbear. Unfortunately, I missed the lively debate there. Sentiments like "if you suffered under the Soviet Union, you deserved it, because only fascists suffered" were much more common than any discussion of how fucked up the ethnic cleansings of the party were under Stalin. Or how the great purge in general weakened the Soviet Union.
The prison system was bad. As were many other prison systems at the time. It's undeniable that they were used for political intimidation and sometimes even petty personal revenge (see the whole Lysenko-affair). Shutting down the discussion around with ""Gooolag hundreds million dead" isn't helpful either.
As for repealing for example the decriminalization of homosexuality, this was done in the interwar years between the civil war and WW2.
I don't think it's reproducing CIA proganda to say that Stalin's leadership had a negative impact on the project of the USSR.