Interestingly enough (at least on Aether data center), I've noticed silver and gold players tend to be quite calm in matches and most of the rage I see comes from bronze players. Additionally, players I see raging aren't doing particularly well themselves when they go off on someone. It's common to blame nerdrage on a competitive internet environment, but I sometimes wonder if it's actually a kind of cognitive dissonance people use to defend their skill level if they lose tons of games.
I suppose the best analogy I can come up is the 0/4/0 mid in LoL who blames the jungler for his deaths. Edit: A better analogy might be from StarCraft II where it was common to flip out on someone after a game if they lost to a strategy they didn't find valid (cheesing was, and maybe still is, really rampant in that game).