Rehabilitation Centers ?

Unfortunately i have had more than a couple friends go to prison throughout the years and it has broken the heart of everyone who loves them, not to mention turned the friend themselves even more angry and violent than when they entered. The stress and worry about how they're doing takes a lot out of both friends and family. But the emotional rift caused by my Friends incarceration is not what i want to talk about. I am blogging about the fact that they-the private owners of the prison-call it a "Rehabilitation Center" implying that their goal is to improve the inmates life when in actuality they do as little as they can to keep the inmate alive and in the system while they make money off the government contract. If the facility was really meant to rehabilitate than why is there a 70% return rate on prisoners?