All human morality is subjective. Not only that, it's very anthropocentric.
Think about it. What's the one thing an animal, wild or domestic, can do that will guarantee its death? Kill a human. Why? Because we make the rules. If a dog kills another dog, nobody bats an eye. Sometimes there's consequences for the murderer dog, but for the most part, people just move on. But let that dog kill a human, and it's a death sentence. Instant.
As for the rest of the rules? Again, anthropocentric. Don't steal, unless you're stealing from an animal, then it's okay. Don't assault people, but you can assault an animal. On and on down the line.
