If prisons send a message, who is that message directed at? IMO prisons serve the functions of deterrence and rehabilitation - although not well - but they als

If prisons send a message, who is that message directed at? IMO prisons serve the functions of deterrence and rehabilitation - although not well - but they also serve to keep the public happy. We put criminals in prison to sate the public’s need to see justice done. Even if we had the perfect rehabilitation regime that would just “cure” criminals, I think putting it into practice would be an uphill battle if it didn’t entail doing some kind of serious harm to the convicted. People want revenge. Prison is a controlled method of providing that.