I learned back in college (in the 90's) that one shouldn't post using his/her real name and email, if for nothing else than spam.
Based on what was shown in the linked article he didn't post anything that bad, but still, he was stupid, and he paid for it.
I think I can say with 99% certainty that he was offered the possibility of resigning, or the possibility of being fired if he doesn't resign. And he was stupid there, too. Last time I had this offer, I chose the latter, and got almost 6 months of paid time out of it. And he could've sued for wrongful termination, too.