The 6.0 review I don't think was the issue. His comments in the video is probably what did it. Saying 'Multiplayer is interesting, but I don't think this game is worth buying' is probably what got Eidos really upset. If I put that much advertising on the site, having the reviewer explicitly say not to buy the game would have seemed like a slap in the face. I think the other critiques were fine and not fire worthy.
I hope Eidos and GS gets lots of negative publicity over the this. I actually liked Gerstmann's reviews. I'd rather have someone being overly critical and still give a high score (> 8.5), than read a game informer review which just boosts its average score.