Lots of people never reach more advanced stages of moral reasoning. They don’t do bad things to avoid being punished, or maybe because they have a simple understanding of “it’s against the rules”

The current justice and prison system is abhorrent, but something needs to happen if someone tries to murder someone else. Most people are alright but there are a lot of anti social people out there, too. And a lot of people who would be alright if they were in more stable circumstances