The nuances of the PRC's desire for a One China policy largely stem from the Marxist theory of Nations, along with a desire to throw off all western colonizers. Without understanding the depths of the "century of humiliation" you can't hope to understand the desire for a unified China.
Secondly, the PRC's process means social change comes slowly, but it has been improving. Notably, Xin Jing, a transgender woman, is one of China's top celebrities. Change is slow, but is happening at different rates across different sections of the PRC. Social change comes from improvements in productive forces and focusing on people as a priority.
Thirdly, nobody is saying the PRC is Anarchist, but your insistence that everyone agree with you saying the government is by definition a tool of oppression despite 90%+ approval rates stands at direct odds with the people themselves. Like it or not, you must face the reality that it is Marxism that has brought great improvements to China's conditions, and these improvements are continuing at a rapid pace, and thus has widespread support.