I went and watched a sports riot once. The majority of the people around were like me, there to watch.
It was a small minority that were setting police cars on fire.
I don't think the sports allegiance caused the riots, they just happened to be the thing that the riot coalesced around. There was certainly a feeling in the air that there was going to be some riots in that city (friends and I drove in from ~1 hour away), and I think many of the actors went there to take advantage of the (so to speak) opportunity, not because they were upset about the loss.
It was a small minority that were setting police cars on fire.
I don't think the sports allegiance caused the riots, they just happened to be the thing that the riot coalesced around. There was certainly a feeling in the air that there was going to be some riots in that city (friends and I drove in from ~1 hour away), and I think many of the actors went there to take advantage of the (so to speak) opportunity, not because they were upset about the loss.