It's because they're winning despite:
22nd best rush offense (Seattle has the 3rd, and Washington has the 1st, and we all should know by now how much a strong running game helps a young quarterback).
26th best defense (meanwhile RW benefits from having the 4th ranked defense)
Meanwhile, he's thrown or a NFL rookie record 4,374 yards, has thrown an NFL rookie record 627 passes (showing that HE is the only pillar they lean on on offense, meanwhile the Seahawks get just as much from Lynch, and if not for the threat of Lynch, RW is probably only 75% as effective), most passing yards in a game for a rookie, and most 300 yard passing games in a season for a rookie. East Coast Bias? Or maybe you guys just aren't paying attention to the other two great rookie QBs (and who could blame you? You've GOT one of them. I'm sure Colts fans and Redskins fans are just as oblivious to RW). In my opinion, each of the three has done enough to earn the honor. I would be happy with a three-way tie, if it were possible.