This is btw also common practice in Germany and France. Prisoners who want access to sports, more than 1 shower a week, a TV/radio, etc ... are only able to do so when taking part in prison work.
Edit: And whether one is allowed to work, and how soon, also depends on whether one gets along with the guards. Work also decides if one can afford to fuel a nicotine or caffeine addiction - if not you have to go beg the Russians, Albanians or whoever runs that racket etc to add it to your tab that you can later pay off with interest ...
Edit-2: what most don't seem to grasp is that a large percentage point of those inside are usually on the streets in cold countries and rather get locked up than freeze to death. Another sizable percentage are refugees escaping conflict zones and that fell through the cracks of a system that should have given them ptsd treatment. Not everyone inside is there because they deserve doing time.
Good luck with that. Legal slavery is literally codified into our bill of rights.