AFAIU, persecution of fundamentalist religious sects has never stopped in Russia; it preceded and succeeded the USSR. It might not often have the same imprimatur of the state as more notorious persecutions, but there's plenty of evidence that it has occurred up until this day. For example, this year there's been a crackdown on Jehovah's Witnesses, though I don't know if it's been nearly as severe as previous crackdowns. I don't care to debate whether these sects deserve to be let alone. My point is merely that the Russian police state can be exceptionally harsh. You can still find people and groups systematically traumatized by it; people and groups whose real experiences expose the ridiculousness of American conservative equivocations regarding persecution. The closest equivocation one could maybe reasonably make is to how the American state treats its black populations, but it'd still be a tenuous comparison. And even that disregards that the Soviet gulags were on another level entirely.
I can't know for sure whether my old co-worker was telling the truth. But there was plenty of circumstantial evidence that aligned well with the story. And while I don't know the precise timeline, it's not necessarily relevant.
In the USSR after the War, if you merely criticized the Party line (e.g. say "We are a Communist country but the Proletariat is rarely consulted by the Party, I think the Party has to pay more attention what the working class people think.") you'd get the treatment ardit33 described. You would not get arrested, you would not be thrown in prison, you'd just get, what they called "wolf's ticket" - a record of "anti-soviet agitation" and then you would not be able to get any decent job, ever. People worked as janitors or threw coal in the communal central heating. Usually a single case of doubting was not enough, you'd get a talking first (quite unlike Google, it seems). Only people who directly opposed the Party were repressed with prison/mental institution.