Fan's the go over the top cheering are usually seeking some sort of validation.
If they get the opposing fan base to react, they feel validated that their passion for their team, and their team winning matters.
In the end, none of it REALLY matters. We watch football for sport. For fun. Mortgages are seldom paid with college football wins, except for the coaches.
Every fan base has crazy fans who really feel they are part of the win. But some people come from areas where their football team is literally all they have to validate their lives as having much meaning. I know of "fans" to the east who are now MLB baseball fans because their team made the playoffs, but to this point, they wouldn't know if the Yankees and Red Sox played in the same division or not. But now, since "their" team is in the playoffs, they are now baseball fans where previously they never watch a game.
If you really start to think about it, why are you letting someone's passion for a football team bother you? It might mean you care too much about your own team and not enough about other things in life to have a good balance.