Postal over what?
Serious answer: Politics. But really what happened was he was asked not to insult someone after he himself was insulted. Instead of walking away, he chose to escalate things because he apparently does understand the concept "walk away." He chose to play internet tough guy.
Outhouse answer: The fact that his avatar wouldn't show when he posted from a mobile source. So this is really Jude's fault. Everybody should start sharpening their pitchforks and preparing their torches. And given Jude's size, we need extra pitchforks and extra torches.