Maybe it's because it's not complicated...not much nuance.
Dem Conv ==> Net loss in poll numbers ==> no bounce for Kerry.
Repub Conv ==> several points lead and double-digit net ==> bounce for Bush.
John Kerry doesn't understand.
While it's true that sometimes life is more like chess than checkers, the public perception of and reaction to the candidates after each convention is more like checkers.
One other thing that I think people are responding to. If you watch Bush and Kerry after their conventions, only one of them has really found his voice. Bush has never seemed more sure and stronger than he has seemed in recent days. And Kerry and never seemed more convoluted.
I think (and have said this for some time) that Kerry is so much the politician that he can't reveal the real him to you...he doesn't know him.