Because no one in prison is there because they’re, like, criminals responsible for their own actions or anything.
Let’s just assume that people in prison actually deserve to be there. Which is a HUGE assumption, some 5% of cases send people to jail even though THEY COMMITTED NO CRIME, not to mention plea deals which send people to prison who might not otherwise have gone if our courts and lawyers had more resources and time to fight the case. Never mind all the people forced to some sort of crime because of poverty or the countless people who committed victimless drug crimes or other like crimes rotting in prisons.
Forget about all that, and just assume that they all deserve to be incarcerated. And as a society we have decided it best to give them the option, sit here in this jail cell, in an American prison (which is incredibly dangerous for all sorts of reasons) OR you can leave, and fight fire for .26 cents an hour. You get money that you can’t spend outside the prison and job training you can’t use once you get out. But not only that, firefighting is dangerous and arduous work.
But if we’re not giving these people a leg up on the outside by letting them save money, or use their job training on the outside, then what’s the point? Other than free labor and more hands on the fire line. American prisons don’t care about rehabilitation, but they’ll take all the free labor they can get.
Now consider that a significant chunck of people in prison would probably be better served through other forms of intervention. Be it substance abuse classes, mental health care, or just job and life skills training, but instead they get to dig ditches and risk their lives for $5 a day they can’t spend outside the prison. If we lock people up for little justification, do very little to help them once in, and even less once out, but work them to death while they’re serving their time, how is that anything but slavery?
If you were serving time for something minor and were asked if you’d rather fight fires or waste away in your cell, you’d say yes too probably. And when you got done risking your life and all you got was a few dollars worth of candy/chips/basic necessities from the commissary, and couldn’t even work as a firefighter when it was all said and done, you’d feel like a slave too. And it would be justified, because that’s basically what you were and that’s basically what thousands of prisoners risking their lives to keep people safe are right now.