I seldom wonder; what is that the Chinese government aims to gain from all this oppression? What any government hopes to gain? North Korea, Cuba, Venezuela, China, Russia (?) etc....What exactly do they want?
Governments, by definition, are meant to "Govern". Most see that the the rules of governance that they, as experts, have defined, should be "The Only Rules". They have a vested (if only intellectual, but rarely is this the case) interest in seeing people follow these rules. Any discussion, or debate, regarding alternative rules, is obviously being pushed by people who don't know what they're talking about.
It's oppression based on consensus and bureaucracy. Sometimes it's nefariously directed, but often it's just pigheadedness and arrogance that lead to decisions like this being made.
Although, sometimes it's just downright manipulative pricks holding the reigns. Hopefully this is less frequent than it actually appears to be. I'm giving these governments the benefit of the doubt, though they haven't done much in recent years to deserve it.
You can tell when a country is either totalitarian or when it's heading that way when they begin seeking increased control over the media, when your communications are subject to routine governmental monitoring, when you can become criminally suspect for having cash, when they're afraid of you being able to encrypt anything because it might be Terror/ChildPorn (read as "forming plots against them"), etc.
Most of all, they don't want to end up dead like Saddam and Qaddafi.
They have valid fears of that becoming reality. Just like other politicians....
The only hope is for oil to just run out.