The idea behind the criminal justice system used by most of the world is a simple one. If you break the rules of society, and are proven to have done so, the state punishes you.
This is the model of justice I was raised with. It’s simplistic and easy to understand. Bad people commit crimes because they’re bad, so we put them in jail.
As I’ve gotten older, I’ve come to realise the world is a lot more complicated than that and that society does itself no favours by committing to incarceration over rehabilitation.