In fact, there's plenty of evidence that prison is, in many cases, a net negative, as it takes people who committed crimes of opportunity or poverty and turns them into either hardened criminals who see it as a lifestyle, or people who have no choice but to commit crimes to survive, as we treat them as nonpersons and shut them out of society.
There is zero evidence prison is a net negative for society. No one is running RCTs here. Progressives advocating this stuff completely ignore second order effects and we see them play out in west coast cities. The other major fallacy is that criminals can or want to be rehabilitated -- they mostly can't or won't. Prison is undoubtedly negative for the criminals, but that doesn't mean it is a net negative for society.
In fact, there's plenty of evidence that prison is, in many cases, a net negative, as it takes people who committed crimes of opportunity or poverty and turns them into either hardened criminals who see it as a lifestyle, or people who have no choice but to commit crimes to survive, as we treat them as nonpersons and shut them out of society.