If you have nothing but the bare minimum, things can't be removed as punishment, the group won't care about losing privileges.

We don't want to release men driven to be animals because they had to fight each other over scraps of bread. We want to release people who have learned some form of trade if they did not before, proper medical management of mental illness and learn how to be in a society of people...

This is probably a built up group of prisoners that are all on the up and up. They get cool privileges, it might filter out to the others and the very violent and non helpable folks will take more effort but everyone else will be easier