If you want a society where premeditated extralegal violence is “good”, you can always go to Pakistan. That’s exactly what people who perform “honor killings” believe.

The developed world got rid of that when duels went out of fashion. The problem with killing someone to solve a problem is that it creates more problems. The person who died has friends, family, children, etc. who will not think your actions are justified. They will come for you and your family.