The way I see it, this only applies when punching up. You don't want someone with a major victimhood complex assassinating people. You also have to be worried about tribalism, differences in what you consider harm, and proportional response. The tribalism point is especially relevant as an evil man can become a martyr and the one killing doesn't necessarily have to be just as bad to become evil in the eyes of others.

Citation: Charlie Kirk's death, Luigi Mangione, the Concept of Bloodfeuds, everything going on in the Middle East