In Punisher: Circle of Blood they covered that very issue. When everyone thinks the Punisher killed Kingpin it creates a mob war to fill the vacuum in which innocent people are killed. The theme is reinforced with a subplot that has Tony Massera, the son of a mobster that the Punisher killed, getting guilted by his uncle to give up med school to seek vengeance on the Punisher. 
Nearly every MCU hero is a killer so there isn't really a moral debate to be had with most of them besides Daredevil or Spider-Man. Jessica Jones would of probably saved more lives if she killed Killgrave sooner.