Here's the way I see it. Humans achieved dominance over planet Earth through superior intellect.(However you believed this happened.) As such that puts us above animals, on a higher place on the food chain, I'm not saying it is ethically right to torture or kill an animal for no reason. Although, if you are attacked by an animal that animal needs to be put down or placed in a place where it can do no harm to humans. And, as highest being on planet Earth's food chain, it is our right to reap the benefits of other species, and we will most likely keep our place on the food chain for the simple reason, that there is already sentient life on this planet so the probability of another species evolving to the point where it can gain sentience is next to impossible. If you were attacked by a fellow human, and somehow you managed to get it onto the ground, you would kick it too (I am aware the bird was dead). Its human nature to be spiteful and want revenge, thats just the way our minds work. (Except for few individuals)
Edit:
And as to Blockoman's post saying roughly, "Animals have to kill other animals to survive" human beings are a type of animal a highly advanced animal albeit, but still an animal. We too as humans must kill animals to survive. Without the meat producing industries the world's economy would crash. Most humans cannot live off a diet of non-animal products alone. Not that I have anything against Vegetarians / Vegans but not many people can take up that lifestyle.
