I think the city of Detroit had a big headstart on the 'thugery reputation" long before the infamous "Little Fallujah Incident". I still remember when Leon Spinks, the World Heavyweight Champion at the time, got mugged in Detroit. Some guy, who was apparently tougher than the World's Champ, took his money, fur coat, and gold teeth.
No, the reputation of Detroit was established many years ago. It was not altered much by local basketball fans, Ron Artest, and the cluster of b-ball thugs.