> Why is that a bad thing?
> I mean I’d rather they were...
> They should be oriented towards rehabilitation.
You said it yourself. It's a bad thing because they should be oriented towards rehabilitation.
These systems steal life and the opportunity to have a life beyond prison walls. Like you also said yourself, the world isn't perfect. As such, people aren't either – we make mistakes. Sometimes we make mistakes due to influences more powerful than ourselves. Slavery doesn't seem like a sound correction to this reality.
I do believe we need consequences to help us feel guilt and the overall gravity of our errors in order to begin to recognize what went wrong and what we need to do differently. But exploitation of another human being doesn't teach them to be more human, but rather, it will tend to dehumanize them. This is why this system perpetuates problems more than it corrects them.