China is not a free country; there isn't free information or free speech. I'm sure that many North Koreans also think that their country is perfectly fine and Comrade Kim is the best leader they could have. The pig in his sow likely thinks that he lives his best life. Does it mean that it's true?
Most people I discussed it with, including PhD students, had very little knowledge of their country's history in the 20th century, of what really happened during Mao's rule and after.
Besides, China is a country socially deeply divided, and the PCC doesn't incentivize social empathy in its population - quite the inverse. So I'm not really surprised that rich kids in USA universities (so, the top of the cream of the regime) don't complain about the system and have never experienced hardship personally.
Have you discussed it with people who were locked up in their buildings during Covid? Or farmers who were evicted to make place for promoters who bought their land on the cheap? Or maybe the Tibetan monks that immolated themselves to protest against the destruction of their culture? Lu Xiaobo, Nobel Peace prize, who spent the rest of his life in prison, for saying the wrong (non violent) things?