I was watching this Family Guy episode earlier and had to post this .gif!
As with most discussions like this, contextual factors really do come into play. Some sport treat the animals that it features in a very legitimate manner, trying to emulate natural circumstances while taking care of the animal in question to be at optimum level. This then leads to a showcase of human and animal working in harmony, striving for victory at the top stage and it is rather beautiful sight, in my opinion - as cliché as that may sound! However, those sport who mistreat animals for the sake of greed and corruption are frankly disgusting, regardless of tradition. I'm normally not for a scenario where the minority ruins a situation for the majority; however in this case, for the safety of the animals, I think that not allowing the use of animals in sport will reduce the not so rare cases of animal abuse for the sake of "sport".