He was still in the wrong, given his behavior in the game. Psyonic's behavior was inexcusable, but that doesn't suddenly exonerate the other player from being a complete d-bag.
My opinion: I agree that firing Psyonic was the only reasonable response, but at the same time, I think people here are being far too happy about it. I definitely disagree with Pendragon's decision to make a thread about it on the forums. He deserves to be fired--he doesn't deserve to be publicly harassed and humiliated by the community.
To use the example that others have used--if you're working in a restaurant and you harass a customer, you're likely to get fired, but in most cases, it's going to be done discreetly, and with some respect to your dignity. The restaurant doesn't put up a big plaque with your name on it saying "don't worry, we fired this guy!"
Maybe they are taking this as an opportunity to nail a few more trolls.
Either way there will be no "side" that arises victorious from this situation.