These are still human beings, and the policies around imprisonment in this country escalate the level of violence rather than decreasing it.
If you are in favor of punitive imprisonment as a form of torture then I would understand your position. That also seems to be the commonly held position by most people within the prison industrial complex as well.
The largest problem in the prison system is its use as a housing mechanism for the mentally ill thanks to Reagan era policies that defunded mental institutions. The second largest problem is gangs, and that is a tougher problem to solve.
What I know for sure is that what we are doing is not working, and there are a plethora of examples in other industrialized countries that we could point to that have done a better job rehabilitating inmates or at the very least decreased the levels of violence between them.
I think your argument is a gross oversimplification of the issue, and comes from a place of ignorance regarding the absolutely inhumane treatment we subject incarcerated individuals to in this country. There simply is a better way on societal level to prevent people from becoming incarcerated in the first place, dealing with them once they are in the system, and providing resources once they have completed their sentences.