Don't understand this at all. Liu Cixin is not a dissident in the slightest; he's beloved in China and obviously supports the Party. The actual Cultural Revolution was not 100% good; why would any future super advanced one be 100% good either? The CPC itself admits much of the Cultural Revolution was disastrous. China is not a perfect place; to not critique aspects of the country would be irresponsible. You can be critical without being disparaging. Liu wants China to be better, that's why he's even mildly critical. He's not some brainwashed Chinese-hating race traitor or something. Look at this interview excerpt he did with the New Yorker (read it here: https://www.newyorker.com/magazine/2019/06/24/liu-cixins-war-of-the-worlds)

When I brought up the mass internment of Muslim Uighurs—around a million are now in reëducation camps in the northwestern province of Xinjiang—he trotted out the familiar arguments of government-controlled media: “Would you rather that they be hacking away at bodies at train stations and schools in terrorist attacks? If anything, the government is helping their economy and trying to lift them out of poverty.” The answer duplicated government propaganda so exactly that I couldn’t help asking Liu if he ever thought he might have been brainwashed. “I know what you are thinking,” he told me with weary clarity. “What about individual liberty and freedom of governance?” He sighed, as if exhausted by a debate going on in his head. “But that’s not what Chinese people care about. For ordinary folks, it’s the cost of health care, real-estate prices, their children’s education. Not democracy.” Liu closed his eyes for a long moment and then said quietly, “This is why I don’t like to talk about subjects like this. The truth is you don’t really—I mean, can’t truly—understand.” He gestured around him. “You’ve lived here, in the U.S., for, what, going on three decades?” The implication was clear: years in the West had brainwashed me. In that moment, in Liu’s mind, I, with my inflexible sense of morality, was the alien.