Not just permitted, but actually widespread. If you’re imprisoned in Texas, Georgia, Arkansas, Alabama, and Mississippi, you are going to be doing unpaid forced labor which is slavery, and many of the prisons are privately owned.
Federal prisons pay roughly $0.12 to $0.40 per hour for regular jobs, which isn’t much better.
The hypocrisy of the US is breathtaking sometimes, and the current administration has the gall to criticise europe.