My impression is that it has to do with Tiananmen Square (been there, tried that, didn't work) and being complicit in trading off economic advancement for maintaining Communist party rule. Also many government officials directly benefit from economic advancement via bribery/corruption.
> being complicit in trading off economic advancement for maintaining Communist party rule.
I think 'complicit' might be an overstatement here; it's not like you can just go vote for the Democrats in China right?
I really doubt Barack Obama would be the American president today if the real penalties for advocating for the replacement of the Republican Party regime of 2000 had included death, life in a torture camp, similar things for your family, etc.