I visited Tiananmen Square in 2002. Overwhelmed with sadness, I began weeping. Walking further up beyond Mao's mausoleum, some students approached and asked me why I had been upset. I explained my thoughts were with the students and the opposition that had been crushed. They said the students had been stirred up by external agitators. They invited me to meet with their teacher who would explain all. I declined. A vehicle with armoured police came near and the students disappeared.
The narrative in the mainland is basically that they deserved this and it's nothing to be sad about.
I TA'd a communications course and one of the topics of collective memory. I talked about how collective memory is reinforced by society and can just as easily be erased.
I asked if there were any students from China (China is one of my fav punching bags as my family is from HK). I asked "What do you think of when I say Tinanmen square?"
"it's nice. It's really safe for tourists. It's really popular in the summer".
I nodded and solicited more responses.
Then I asked "Anyone from Taiwan or Hong Kong? What do you think of when I say 'Tiananmen Square?'"
The Chinese students were shocked at what was coming out of their classmates' mouths.
China has done an impeccable job of pretending this never happened for the younger kids.
For older people, there's a combination of "outside agitators" as you say, and also a "kill the chicken to warn the monkey". If they didn't do this, how can they control a population of almost 2billion people? It was necessary to deal with these bad actors and it was well deserved.