Once you are already in prison it's hard to say whether you are forced to do it or not. It's not like you have a lot of employers and professions to choose from. And if the incentives include things like easier to get parole then refusing to participate would mean more time served. It'd be pretty hard to prove some labor is not "forced" in a prison setting.
This is a way over simplistic view. It's not a CIV game where someone decides what "China/Han" should do for all these thousands of years. People's minds change, sometimes the people themselves change, accidents happen. You don't have to find some hidden "truth" that goes back 3000 years to explain what China today does.
For US it will. People in the US seldom think about just how powerful their media environment and general influence is. Like women have been sexually harassed since forever in China, and it's the #MeToo movement that led to a lot of the victim to stand up and people to support them.