I'm with Penny Arcade on this one, if people had heard half the shit I said (always in misguided jest) when I was that kids age, I'd be in jail for the rest of my life. What he did was really stupid, but guess what? Kids are idiots, they do shit like this all the time, that doesn't mean we ruin their lives for it.
Intent is all that ever matters, and it should have been blatantly obvious to everyone that this dipshit had no intention of doing what he said.
The thing that really irks me is that I guarantee you, for every kid who says something dumb like this on Facebook and gets Team America: World Police kicking their door in, there are a hundred others who say stuff just like it, or worse, in real life without repercussions just because they're lucky enough to not be overheard by a kneejerk reactionist.