I think that recovery for these people is entirely possible through faith in a higher power and the ability to be honest about their problem. If they are a threat, they shouldn't be let out in the first place - let the potheads out instead if crowding is a problem. And if sex offenders are let out, conditions should not be imposed on them that may likely drive them back into their old pathology.
I believe they can change but it is up to them. Just like any other disease out there, you have to work hard and keep yourself sane. But with "these people" I don't believe they have the heart and mentality to change.
I was searching for information about my case (which happened many years ago) and came across that he had nine different charges against him. And that was all after he had been let out after mine. Who knows who else is out there too scared to say anything. I almost didn't say anything, but I was so young that I didn't know why he was doing this all to me.
I don't believe he can change, but I believe someone out there can. They will fight that urge EVERYDAY and it will never go away, but I believe that some can change...He won't, but some will.