They let them out because they believe they are no longer a threat. That's different than what people call their debt, in that it is just a portion of the total

They let them out because they believe they are no longer a threat. That's different than what people call their debt, in that it is just a portion of the total debt. If not obvious, I don't agree with that sentiment. I think prisons should be about reform more than debt or punishment. Very few people pose a real risk and a significant number of them could be reformed, if studies are to be believed.