Who cares what a persons or groups motivation is to kill a NM/HNM... Many want that kind of activity and that should be reason enough to include them in the game. If I don't fancy killing them I wont. Simple as that.

They do need to be implemented well to prevent them being overly monopolized but lets not throw the baby out with the bathwater....

Also, I went and killed WNMs just last night, but I am probably "No one".