The DMCA has been used to squash criticism before in difiance of the 1st ammendment, and the corporations that abuse it never go against anyone with the lawyers to get it in front of SCOTUS so that section od the DMCA could be nullified.
At first it appeared that GameSpy was abusing the DMCA, but what it was is thatt they didn'y only rely on the DMCA and just used it for additional clout (let their laywers who only care about money right the letter) and they had a justifiable reason to go after the man. While going after his adviserories is a bit excessive, he did have it coming due to piracy software he had on his site and he had tried to extort a "consulting fee" from gamespy in the past.