Here is a difference, as I see it, RED SOX (baseball) the game that they play is simplier to understand. Also, one player (pitcher) can dominate a game. So RED SOX & baseball fans think that they know everything about it and can act like that way.
Football (Patriots) is a much harder game to understand. Football is also evolving all the time. Football is the ultimate team game no one player can dominate a game without all of his teammates doing heir jobs. That is why football fans are less arrogant than baseball fans.