I know nobody takes this guy seriously, but this is some terrible shit talking right here, and since you asked what everyone thought, keen to oblige! Especially given the decidedly poor state of this thread so far.
To start, it must be said, the funny thing about .M. (and it's possibly the first time I've experienced it quite like this), is the members don't particularly care about winning the world. Our original leader unfortunately had to leave the game, while no other players had the particular urge to pick up the mantle. And even when that happened, we were clearly a considerably smaller tribe than the front runners. When fact is, most players in .M. are not here to win, we haven't brought in multiple players from previous worlds to take over accounts and we're definitely not about picking the winning side or merging. Not only are we alone in being the only non-premade out of the final big tribes, but the vast majority don't even have coplayers (these account sitting restrictions are really killing us right now...). Don't get me wrong, .M. have some top players, but the players are really just here because they enjoy playing the game with one another, not out of any grudge or desire for anything but fun. There therefore was no 'leadership' or central decision of any kind, because .M. is much more a true 'tribe' than most. Reg, on the other hand, has only ever proved himself an excellent leader, and although he never asked to be so, stepped up when required and played the role flawlessly.
In reality, the decision to turn on AMG wasn't Reg's decision alone, it was because the tribe didn't want to be allies with someone who would try and take a dump on them at every turn. We became allies as the world was dividing between two lines and we picked a side that was picking us. But since then, we have only ever been allies in name only. And when someone treats you like shit and don't honour their commitments (and more than that, actively work against you), your commitments towards them start to mean progressively less and less. There was no desire for gain, only to fight against those we disliked the most. To continue the classics theme you so faithfully followed; think less the betrayal of Helen of Troy, and more Spartacus's slave revolt. To turn on your true enemy is less a betrayal, much more a justice.
Saying all that, I feel sorry for design that they had to ally with AMG, as there was always largely an ok feeling about them. But it really does go to show AMG and those like them; act like a dickhead, get treated like a dickhead. Will this revolt go well for .M.? Who knows. But at least we know we're going down fighting for the right side if we do.