The passionate fans usually have one connection to this passion for the team. They're parents, or at least siblings or grandparents. Go to any high school game and you have more than just parents, family, or friends. It doesn't even take school rivalry. Now think of soccer.
All infringements are immediately on the play.
A foul almost always occurrs in the vicinity of the ball. So everyone is watching the same thing, the same players, the same incident.