I think this is the first time U2 have outright CANCELLED a concert since the Raleigh show on Popmart. They've postponed shows that were later rescheduled, but they rarely outright cancel. For them to not even try to reschedule probably means that they are left with no other option at this time. Most unfortunate. I'm not going to comment on the reasons for the riots, 1. because I'm not as informed as I should be, and 2. I make it a point to never debate political matters with strangers on the internet. I definitely understand their reason for canceling, the local police have more pressing matters to deal with. If tonight were something like a football game, that too would have been cancelled.
I feel bad for all the fans who altered their lives to make plans to go to this show, especially those who were traveling from a far distance. I suppose now St. Louis will be played on the next tour, so look forward to that. Stay safe, everybody!