Without God, we are left with the expectation that one's position on a given moral question should be supported by a more general ethical principle. What we are usually measuring is not the inherent goodness or badness of our ethical standard, but how coherent and consistent it is. And I can easily come up with a consistent standard that permits rape, murder, and mayhem. Or maybe it's the fact that we all agree on the fundamental principles that makes them good. Then again, think about Manifest Destiny, or the 'naturalness' of slavery.
Music is a good.
Killing things for fun, and self-disembowelment in public are bad. I found Mr. Saletan's arguments on zoopedia to be fascinating, but I'm afraid that he's missed an important point regarding consent. He implies that human sex with animals would be OK if only the animals could offer their informed consent. He suggests further that animals with the minds of children are incapable of offering consent. But by that argument, these animals can no longer have sex with each other, because they are incapable of offering consent.