REHABILITATION
There are a lot of issues mixed up here, so I'm going to try to tease the threads apart and make it clearer, and I'm going to label them to keep them separate. One of the most important ones, which so far as I can see everyone has breezed past so far, is the oft repeated factoid "rehabilitation doesn't work." People who advocate the sort of policies described here have to believe that, or their arguments break down, but that doesn't make it true.
The fact is that there are well established systems of rehabilitation which have been trialed many times over many years with a wide variety of subjects in many different institutions, and they work. They don't claim to turn a villain into a saint, but they do reliably show a massively lower rate of re-offending than any purely punitive regime. In other words, if the object of a judicial sentence is to prevent crime by preventing criminals from re-offending, rather than to make people feel better by making someone suffer, rehabilitation works better than anything except punishing every crime with death or life imprisonment.
The reason these methods have been successfully trialed so many times but never applied is that they involve such things as treating convicts like people, talking to them sympathetically, rewarding them for good conduct, and a range of similar things that Ian would call "being soft on villains." So despite the many proofs that this would be the best possible policy for reducing crime, no politician would dare to even suggest rolling it out over the prison system, because they know the storm of tabloid outrage that would sweep them from office long before the benefits of the reform could be seen.
Unfortunately, the result of this official cowardice is that we now have the worst of both worlds, with a system that is too brutal to be reforming and too lenient to be punitive.