Because the media and most fans have very little analytical skills. It basically comes down to whether they love or hate the QB. And then just like how a QB gets too much credit when the team wins and too much blame when they lose, predictions become skewed out of proportion based on that love or hate. So all the people who hate on Henne and don't understand football enough to see the impact of the OC, will ignore how the offense and Henne looked in the preseason and won't even remember how good the defense is. And those people are not even self-aware enough to realize that's what they're doing. They'll dress it up with some pseudo-logic that lets them convince themselves that they're being analytical, but in the end it just comes down to whether they love or hate the QB.