I guess what I mean is, they can't end up squeezing prisoners any more than they already are: in many places 8 hour prison jobs paying less than 50 cents a day, when a phone call costs $3.00+ an hour and a single ramen noodle costs $2.00+.
That stuff significantly contributes to the prison mentality and group-think mindset of 'the authorities are your enemy'. Even if you don't come in with that mentality, after being surrounded by it in conditions like that, you'll very likely be brainwashed by the time you leave and the cycle unfortunately begins.