That's just like saying, "What makes a person killed on the streets different from a person killed in war?" An animal killed for food is a necessity for populations of humans to survive, but an animal killed for fun does nothing but provide a sick pleasure for one. I'm not saying animals should be treated as slaves, but humans have a world of advantage over animals, and that's why, biologically, we are superior.
I, however, hate cruelty of animals, but need the resource of meat to provide me with the essential nutrients that other types of food can not.