This hits different for me because my brother just got out last year. You're right - he didn't want to be "rehabilitated." He wanted to not be treated like a permanent criminal. What killed me watching him inside was the contradiction you're naming. He had to prove he was sorry, prove he'd changed, do the classes, be the "good inmate" - meanwhile the actual conditions are dehumanizing. You can't become more human in a system designed to strip your humanity. That's the con.
What actually changed him? Honestly? A counselor who didn't see him as a redemption project. Someone who just treated him like a person trying to figure things out. And time. And getting to leave. That's it.
But here's where I push back slightly on your framing: I don't think you're wrong that the system is broken, but I'm not ready to say rehabilitation is the *wrong* goal, just that it's been perverted into something toxic. If we actually had systems where people could heal and change *without* the punishment structure, without having to perform repentance - would that be bad? I don't think so. I think the cruelty is baked into how we've set it up, not the idea of change itself. We just need to stop treating growth as something people owe us.