The dude snapped when he’s loved ones were killed, that is considered exculpatory of violent actions in almost all legal systems. The difference is that instead of a knife or a gun he had almost omnipotent powers of destruction.
In an ideal society he would get psychological counseling to deal with the trauma and ensure it doesn’t happen again, but I think it’s obvious he was a bit above Troi’s pay grade.
Just a little bit (i.imgur.com)