He should of still gone to prison
No matter how badly someone wrongs you, you should NEVER take the law into your own hands. This film just glorifies vigilantism by giving one extreme example.
There are plenty of other examples of vigilantism that ended up tragically for the "bad guys" because the vigilantis heard wrong or ended up maiming or killing the wrong person. We have laws and justice to protect us and must always be obeyed at all times, and not just when we choose too.