I propose that having sex with animals is over stigmatized and should be perfectly acceptable in society; as long as the vagina of said animal would be able to accommodate a a particularly large 8 inch penis.
What is technically wrong with having sex with animals? Surely it's just an overblown sex toy? One could claim that animals are stressed by sex, but animals are also stressed by tractors, other animals, farmers who like yodeling first thing in the morning and a whole host of other things which might affect their sensitivities. Stress isn't really an acceptable excuse to force someone not to relieve themselves with a perfectly tight animal-hole. I propose that the animal sex laws are a restriction on human freedom to pleasure themselves as they will, and if the action doesn't affect the actual physiology of the animal in question, it should be perfectly acceptable.