One thing you do have to realize is, the Chinese are very good at keeping up the appearances.
While there are local elections, there's usually no right to stand for elections. These so-called elections, generally has only 1 candidate, or a few that are all communist members, with pretty much the same views. "Elections" where people can't stand to be elected freely are not elections, they are just some elaborate ceremony to rubber-stamp government official appointments.
that is unfortunate, it seems anywhere you go people try to subvert democracy (to different degrees of success)... i guess that’s why they call it “eternal vigilance”
so, while indirect, there does seem some nominal way to disagree as you say
[1] https://en.wikipedia.org/wiki/Elections_in_China