But, then again, I'm an avowed speciesist.
What other purpose were animals put on this Earth for? To balance the ecosystem and to provide as you said a benefit for humans. The freaking cheetahs hunt down gazelles to eat and survive. They don't give a **** about the gazelles feelings. Now I don't think you should beat and abuse animals, or electrocute chickens (Reportedly KFC does that).
Queen of the boards. Queen of the world.
Say what you need to say.
But, most importantly, humanity has advanced to a level where we no longer need to sustain ourselves with animal products. A cheetah has a biological imperative to eat a gazelle, whereas we'll eat a gazelle simply because we may find it tasty. We might hide the gazelle's skin into leather (is that even possible? lol), and wear it as clothes or fashion a couch out of it, but we don't need to.