Yeah I think it is very good to support your hometown team, but when it leads to violence then it has gone too far. There seems to be an increase in fan fights and violence in all sports and not just football. A few few weeks ago, a major fan fight broke out at M & T Bank Stadium during the Ravens vs Chiefs preaseason game. That's right it was just a preseason game.
Here is a video clip of the fan fight at the Ravens vs Chiefs preaseason game in August 2011: