The US criminal system isn't meant to rehabilitate, and a corrections officer told me that directly once (after I asked for a Bible and he said no).

It's only meant to provide the public with a false sense of security. "Another scumbag has been locked up, key's been thrown away, you're all safe once again. Enjoy the rest of your evening."

But it's okay because people are easily forgettable. If you have 100 people on a block, and 1 is taken away unjustly, you still have 99 who can quickly forget about that 1, provided they're distracted with enough beer, books, movies and memes.