Sports fans

I was reading articles about fans, and sports fans are the most vicious types of fans ever! I was reading one article and it was just saying how many fans get injured by other fans all the time. I think its ridiculous its a game! Is this normal for fans to get so into the games, basically as much as the players do. I think think violence over a sport needs to end because that is no reason to fight. It would be more acceptable if it was the people actually playing the game because they have a reason to fight maybe. Do people feel the same? or do you think that this is normal and okay for people to fight over a game?