The redditor "Tienanmen Square massacre" narrative is flat earther levels of crank shit and needs to be recognized as such.
This shit has seriously gone on too long. People who continue to cling to the "10,000 dead crushed by tanks hosed i to the gutter" bs are cranks. It's jews control the banks, chemtrails, the earth is flat, the moon isn't real level of crank shit and unless you're feeling very indulgent and someone is asking in good faith it can be dismissed as equally serious to that kind of crank shit.
It's truth or falsehood frankly does not matter to a lot of people who believe this. It confirms their world view and emotionally feels truer than the actual events themselves, which are well documented if they should care to know.
Lol and the concept of brainwashing was invented by the US because they needed to explain why US troops in Korea were defecting, and why defectors and captured soldiers were explaining the war crimes the US committed. "They were brainwashed!"