Spaniards insult the Catalans in NYC during the World Police & Fire Games

From August 26 to September 5, New York holds the 2011 World Police & Fire Games (WPFG),—the second largest multi-sport event in the world, surpassed only by the Summer Olympics—with the participation of police and firefighters teams from all over the world.
During one of the events, the Catalan team built a human castle—a Catalan tradition recently recognized as inmaterial world heritage—and raised the Catalan flag that symbolizes self-determination and independence, while the Spaniards in the event started shouting, whistling and insulting the Catalans, as seen in the following video.
This is not an isolated event. A couple of days ago, for instance, Cesc Fàbregas, player of F.C. Barcelona, celebrated the winning of the European Super Cup with the same type of flag. Some Spanish TVs made a big deal out of it and falsely said that the flag is not legal. In Twitter, the hashtag #CescMuerte (Cesc Death) became Trending Topic in Spain