There is a reason there is a magistrate in court of law who gives oportunity to BOTH parties to be heard before ajudgement is made. All i read in that link is an opinion of a pissed off munchkin.
I see no actual fault of the GM since all he describes are actions the suber mage munchkin primer character took to make the game miserable.
He mentions he ran that super mage in another campaign and got him to be super powerfull with custom tradition. Yea. so yopu bring in a super mage in a 1st session of a new campaign?
I bet there was some issues with the GM that may have been forced to have this dkhead in his group. Some people are not good at saying NO and communication their objection. SO the GM have tried to play along until this super mage broke the game balance with his super spells. So the GM fought back. Possibly split the party to isolate the super mage and remove him without hurting the party.
It wasnt the GM that killed the party. It was teh super mage special mana rift that took out the whole city block and then some.
That blog is a rant of a pissed off munchkin who perverts some facts. If he had proper evidence he would have spilled the play by play and let us find the truth. but his version of thetruth would have had so many holes we would have been able to find the GM was not to blame.
another thing he mentions is the GM had been GMing for the others in the group for a long time before these 2 (super mage and super spy) joined and started ruining the fun. Some groups tend to play low key campaigns and you throw in super mages and abused min maxed munchkins and it breaks the group harmony. Add into that socially inept GM who has no balls to tell other people to piss off when they are breaking his game and you have the ONLY way such a person can deal with opression. Split Personality Disorder. He calls in his GM super powers and throws his weight ingame trying to kill/solve the problem.
I can take a guess and see the other players secretely complained to the GM and he dealt with the problem. Too bad the mage took out the whole group to spite the all.
If I was the GM i would have simply told the super mage "Please dont come next time. Thank you" and leave it at that.