No, the point of prison is to be part of the legal system. The point of the legal system is to keep society hale and hearty. If that means prisons are horrible torture pits, so be it. If that means prisons are touchy-feely slices of utopia, so be it. "Reducing crime" is important, but whether you do it through the carrot or the stick (or a third method or a combination of methods) is up for debate.

So no, the 'point of prison' isn't 'to suck'. That's an overly simplistic view of the issue.