I think this is the wrong question to be asking.
The real question is, why do WoW fans put all their eggs in one basket? It's not just Asmongold, in the past it's been Ghostcrawler (honestly, the MMOC editors' obsession with Ghostcrawler's tweets was embarrassing), it's Raider.IO, it was Elitist Jerks... in short, it's whatever WoW players feel is the paragon of the moment with regard to their thoughts and feelings about the game in general.
But I don't blame WoW fans for this. It's not our fault that anyone puts Asmongold or any of these other people on a pedestal. It's Blizzard's fault. People do this, they look for someone to speak for them, when they feel their concerns aren't being heard. The official forums don't provide that outlet. Reddit doesn't. MMOC and Wowhead and Blizzard Watch don't. Twitter doesn't.
We all think things about this game, positive or negative. More importantly, we want to be heard when we collectively have a voice that needs to be heard. Right now, the developers need to hear a lot of things about the game that many of us feel aren't being listened to. Don't like it when Blizzard thinks they know what needs to be done with your class because they have data and stats, and you casually point out that nobody knows players' classes BETTER THAN THE PLAYERS THEMSELVES and they still don't listen? We want Asmongold or somebody like him to be heard.
As I said in another thread, I'm not a fan of Asmongold personally, but I think he's saying things a lot of people want Blizzard to hear and he's possibly the best shot right now at doing so. But they won't, because they're tone deaf. And that's not the fault of all of you, the players, the MMO-C readers... none of us are the problem here. Blizzard is. They don't want to hear it, and one of these days, that's going to kick them right back in the butt.