It's not rehabilitation, it's slavery with extra steps
The amendment banning slavery says you can still enslave people if it's to punish them for a crime
Prisons are largely privatized nowadays, creating a demand for prisoners as they profit off of the free labor they get from prisoners
Rehabilitation efforts in the modern penal system are largely non-existent, with people usually coming out more violent and criminal than they came in, even if it was a bullshit arrest.
Black people are incarcerated at higher rates and with harsher sentences than white people for the same crimes, they also tend to get found guilty on much weaker evidence than their white peers