Matvei Bronstein: Theorical physicist. Pioneer of quantum gravity. Arrested, accused of fictional “terroristic” activity and shot in 1938
Lev Shubnikov: Experimental physicist. Accused on false charges. Executed
Adrian Piotrovsky: Russian dramaturge. Accused on false charges of treason. Executed.
Nikolai Bukharin: Leader of the Communist revolution. Member of the Politburo. Falsely accused of treason. Executed.
General Alexander Egorov: Marshal of the Soviet Union. Commander of the Red Army Southern Front. Member of the Central Committee of the Communist Party. Arrested, accused on false charges, executed.
General Mikhail Tukhachevsky Supreme Marshal of the Soviet Union. Nicknamed the Red Napoleon. Arrested, accused on fake charges. Executed.
Grigory Zinoviev: Chairman of the Communist International Movement. Member of the Soviet Politburo. Accused of treason and executed.
Even the secret police themselves were not safe:
Genrikh Yagoda : Right-hand of Joseph Stalin. Head of the NKD Secret Police. He spied on everyone in Russia and jailed thousands of innocents. Yagoda was arrested and executed.
https://en.wikipedia.org/wiki/Genrikh_Yagoda
Nikolai Yezhov : Appointed head of the NKD Secret Police after the death of Yagoda. Arrested on fake charges, executed.
https://en.wikipedia.org/wiki/Nikolai_Yezhov
Everybody was absolutely terrified during this period. At least 600 000 people were killed and over one million people were deported to Gulags in Siberia.


Your original (implicit) point was that people who have lived experienced in the era of the USSR disliked it. That’s just not true. All you have is anecdotes - and anecdotes mostly from USians, at that.
No, all I have is not anecdotes. But the anecdotes confirm everything else.
People fled and smuggled themselves out for a reason. You either fall in line and praise the rulers, or you might trip and fall out of a window.
Millions upon millions died under Stalin. And when he was on deaths door, there were hardly any doctors to treat him due to him having them killed, tortured, and/or arrested. Now that is poetic justice. Though it’s hardly any consolation for his victims.