Keep in mind that you're probably mostly reading stuff that's designed to appeal to upper-middle class left-leaning people, about how many people in prison are oppressed, have so much potential, are caught up in an unfair system that's hard to escape, are subject to institutionalized discrimination, etc. There's no doubt that people like that exist, and are probably even a disturbingly high percentage of the overall number of people imprisoned.
On the other hand, there are also people in prison who actually are dangerous criminals, and really need to be locked away from the general population. That is what we created it for in the first place, and why every society has some sort of prison. But nobody writes stories about those types of people, at least not in "intellectual" sites and magazines. When was the last time you read a story about a truly dangerous criminal and what their experience in the legal system has been?