Sign of the times or outraged for the wrong reason? That's for you to decide-- Tobold says his guild has moved on to Serpentshrine, and since he's not attuned yet, he probably never will be, which means there's no point to moving on. Apparently no one has told him about Vashj's attunement scrolls, which will let a guild that beats Vashj attune whoever they want to SSC. Of course, he'd have to wait until his guild actually beats Vashj, but hope is not lost yet.
Then again, maybe Tobold's just going with the flow. If you ask me, leaving because your guild has moved on is a terrible reason to leave-- not only is there lots to do out there, either on your own or with the people in your guild who don't happen to be running SSC, but I do believe there is more than one guild in the game. Surely someone else would be willing to take Tobold to Karazhan, right?
Either way, it's his choice. As he says, cancelling the account sends a clear message to Blizzard that he wants things to change. And if enough people send that message (for whatever reason), then you can't but agree that they will.