As for suppression of free speech, the attitude in China is much more pessimistic about the ability of free speech among the public to produce good governing decisions. There is a difference between speech that can be used to gauge public opinion, and speech that seeks to spur the public into taking rash actions. Currently, governing decisions are made behind closed doors by a group of elites that carefully deliberate their choices after taking public opinion into account. Free speech that attempts to sidestep this process by not just allowing people to air their grievances, but tries to rally people into pressuring the government and seizing the decision-making levers directly are suppressed. At the end of the day, it is an authoritarian system to tries to keep the existing holders of power entrenched. But when the current philosopher kings are doing so well, only a minority of people on the margins of society really want to rock the boat.
At the end of the day, every society limits free speech in some way. The US sets that limit at threatening physical harm on specific individuals. China sets that limit at upsetting the status quo without going through the proper channels.