at some point, strong-arm tactics backfire. we saw this in the iran of the shah and to a point in egypt of today (with the muslim brotherhood).
the reason why it is not worse in china is because, combined with these strong-arm tactics, china has a rapidly growing economy, strict laws (look at the recent Tibet Autonomous Region Implementing Measures), and also- hard to believe, but it's true- some bending over!
China bans images, mention of pigs on TV ads