Rehabilitation and integration are not goals in the US. It's punishment and deterring criminals. It's dumb and antiquated old testament morale beyond believe.
Let's not single out the US for that. There are quite a lot of places (many even worse than the US) that use imprisonment for punishment and as a deterrent, rather than rehabilitation. It's society's dirty little secret, that some members of it just want "Bad People" to be punished.
There are no other modern rich, democratic countries with anything even approaching the incarceration rate or minimum sentencing insanity the US has, so it's entirely proper to single the US out.
Yes, they have old people who dont get enough for a pension. That is troubling as so far, as it prooves that people can in the end vote with there hands and feets against the free market approach of everyone insure himself against beeing poor at old age.
Plus, from my perspective, the first priority of any prison should be rehabilitation and reintegration of the prisoner into society.