Prison work has never been widely regarded as morally repugnant (don't conflate with debtors' prisons, which are fundamentally different), so this necessarily i

Prison work has never been widely regarded as morally repugnant (don't conflate with debtors' prisons, which are fundamentally different), so this necessarily is not one of your aforementioned forms of slavery. At the end of the day, incarceration costs money, and the people responsible for the incarceration would ideally foot the bill. Obviously the incarcerated rarely have such means, but I don't think it's unreasonable to ask them to pay a little bit more than the average law-abiding citizen. I don't have a strong opinion about how they repay their debts--whether it's garnished wages while in prison or after their release, but it should be one or the other. Actions have consequences, and a fundamental purpose of prison is to remind people of that. Moreover, work is a rehabilitating endeavor--it build skills, confidence, and character. It's mutually beneficial.