I never implied that it was a defense. Immature youths have been known to do and say really stupid things. Add hormones to the equation and they can do extremely stupid things. Add drugs and hormones along with immaturity you have incidents like this and columbine. Not saying drugs were involved but I would not be surprised.
I think stories like this just really make you shake your head...these kids could've done a million other things, ran away, eloped, joined and commune, whatever. But rather than do that, this clown murdered her parents in cold blood.
Sure, he's not the first person in the world who's had his girlfriend's parents disapprove of him. But murdering them? Has life gotten so cheap that murder is now a first choice of settling agreements? How long can such a society survive?