The difference is U.S. prisoners are convicted felons. Many volunteer for these jobs, such as the firefighters in California. Others are paid a small wage for their work or get reduced sentences.
In China, it's members of specific minority groups such as Uyghurs who are singled out and put into concentration camps ... not because of what they have done, but because of who they are and what they believe.
Uyghurs and other non-Han minority people in China are subjected to forced labor, forced abortions and idealogical re-education.
Via the AP:
An estimated 1 million people or more — most of them Uyghurs — have been confined in re-education camps in Xinjiang in recent years, according to researchers. Chinese authorities have been accused of imposing forced labor, systematic forced birth control and torture, and separating children from incarcerated parents.
https://apnews.com/article/only-on-ap-middle-east-europe-gov...
The Guardian:
It estimated 570,000 people came through three minority-heavy prefectures alone – Aksu, Hotan, and Kashgar – and that labor programs in other ethnic minority regions as well as prison labor would probably add hundreds of thousands to the figure.
The labour programs are not secret; they are frequently written about in state media as glowing examples of the government assisting millions of poor people into work, but those articles also contain clues to their coercive nature. Transferred workers are often sent far from their home, made to live on site in factories and subjected to ideological training.
Publications on the labour schemes frequently include references to policies discouraging “illegal religious activities” and changing thoughts and behaviour.
https://www.theguardian.com/world/2020/dec/15/xinjiang-china...