Well, I’m not defending cockfighting. But I don’t believe anyone has to force roosters to fight. It’s their nature. They fight for dominance, to decide who will rule the roost.
Of course, adding spurs to their feet changes the game. But I suspect that the winning rooster enjoys it. I don’t know that, since I’ve never watched a cockfight and don’t intend to.
Try a kick boxing match where you both have those spurs on your feet and see how it feels. Something tells me the wounds will hurt just as bad even if you win.