I checked the thread you were talking about, that’s not what happened. The supporting evidence came from a huge number of different sources, including many western sources. You also equated Chinese diaspora with the Chinese government itself, which reeks of chauvanism.

As for the bit on Tian’anmen Square, it’s correct, even Wikipedia says so:

Deaths in and around Tian’anmen Square itself

Government officials have long asserted that no one died in the square in the early morning hours of 4 June, during the “hold-out” of students’ last batch in the south part of the square. Initially, foreign media reports of a “massacre” on the square were prevalent, though subsequently, journalists have acknowledged that most of the deaths occurred outside of the square in western Beijing. Several people who were situated around the square that night, including former Beijing bureau chief of The Washington Post Jay Mathews[i] and CBS correspondent Richard Roth[j] reported that while they had heard sporadic gunfire, they could not find enough evidence to suggest that a massacre took place on the square.

Student leader Chai Ling claimed in a speech broadcast on Hong Kong television that she witnessed tanks arrive at the square and crush students who were sleeping in their tents, and added that between 200 and 400 students died at the square.[268] Ling was joined by fellow student leader Wu’er Kaixi who said he had witnessed 200 students being cut down by gunfire; however, according to Mathews, it was later proven that he had already left the square several hours before the events he claimed to have happened.[211] Taiwan-born Hou Dejian was present in the square to show solidarity with the students and said that he did not see any massacre occurring in the square. He was quoted by Xiaoping Li, a former China dissident to have stated: “Some people said 200 died in the square, and others claimed that as many as 2,000 died. There were also stories of tanks running over students who were trying to leave. I have to say I did not see any of that. I was in the square until 6:30 in the morning.”[269]

In 2009, human rights activist Robin Munro, stated that he was present during the clearance of Tiananmen Square and that, according to his account, there were ten Western reporters near the Monument to the People’s Heroes at the time. He also reported a Spanish television crew that recorded footage of the event. Munro disputed Wu’er Kaixi’s claims of mass killings inside the square, stating that he did not witness fighting there and instead observed students peacefully complying with the soldiers’ demands to leave the square in an orderly manner. He further noted that the Spanish TV crew reported not seeing killings within the square during the final clearance.[270][271]

In 2011, three secret cables from the United States embassy in Beijing from the time of the events were leaked and published by WikiLeaks, all of which stated that there was no bloodshed inside Tiananmen Square itself.[194] Instead, they said Chinese soldiers opened fire on protesters in Beijing outside the square, around Muxidi station, as they fought their way from the west towards the centre.[194] A Chilean diplomat who had been positioned next to a Red Cross station inside the square told his US counterparts that he did not observe any mass firing of weapons into the crowds in the square itself, although sporadic gunfire was heard. He said that most of the troops who entered the square were armed only with anti-riot gear.[194][216]

The square was evacuated bloodlessly, all of the deaths that day occurred in areas scattered around Beijing during riot suppression. A few hundred people died, which is a tragedy, but not 10,000 people being executed on the square like the west initially reported. Substantial evidence to the contrary since then has come out, and Wikipedia has accordingly responded and added this context.

I don’t think Wikipedia is a CPC front group.