SINCELEJO, Colombia — The fans came for the action. The bullfighters for the glory. The bulls, each 1,000 pounds of heaving, sweating fury, had no choice. And so it was that the bulls, one after the other, were released into a vast, throbbing arena, to be faced down by a squadron of horsemen armed with long pikes, dozens of “manteros” with red capes, hordes of young men swinging sticks, plus a clown or two.