Because. God put animals on earth to eat. Dogs? That's a different story. You don't eat creatures that aren't meant for food. However, that doesn't mean you can't eat cows or pigs or chickens etc. I'd never kill one myself, but you get my point, right?
"I see no difference between eating a dog, pig or cow. If the idea of eating dogs or cats bothers you, then understand how the idea of eating pigs, which are just as smart and loving, bothers me. Then you will have understood the daily pain within the heart of a vegan, or at least, ...within the heart of me." ~Jace Kai