I think excluding a murderer from participating in society is a solid choice for the safety of others. Not saying it's the most perfect solution to a problem, but it is a decent solution.
I'm asking about what's happening inside those prisons. And what happens to the prisoner after he's released from said environment. Is there a net benefit to society with the current status quo?
I guess in short a better way to put it is this: Is the prisoner reformed and able to reintegrate with society?