Animals in their natural environment will fight till death with each other and even eat each other, this is going to happen regardless weather human exist or not.
Now human feed them to fight, is that not a kind treatment to them? :*:
Animals knows nothing about brutality, it is the foolish humans trying to impose civility on animals. In animals' world fighting and survival and preying on their meals are parts of normal daily life and no moral standards can be understood nor practiced. Human are idiot who thinks they know a lot and foolishly trying to impose their own silly standards on animals. Animals know how to fight for survival for dominance and control, they know their own rewards and penalties for victory and defeats. They don't care about boxing trophies at all. If you provided bananas or pears it may be recognized by the monkeys.