So basically the fans don't even come to watch the sport anymore rather they come to revisit hostilities with people who they probably don't know based on the fact they support someone different from the same city.
Which they get nothing out of, nothing constructive other than a bit of a adrenline rush which they could get by simply watching a good game of basketball. All while risking getting serious injury by potenitally losing an eye or something even worse.
Makes sense...........