That HIV started by bestiality is a myth it is far more likely that someone ate raw bush meat or got blood in a cut while they where hunting a chimp for meat.
And diseases like influenza and smallpox began as animal diseases, but it was farming and eating them that transfered the diseases to humans, not shagging them.
As for "food, labor, and entertainment", if the animal is in extreme, pain, anguish and distress in those situations, then it's unethical in those situations as well. I imagine raping an animal would cause it extreme pain, anguish and distress.
First, most man-beast sex is male dog on male or female submissive. If it caused the dog pain or distress he wouldn't do it or enjoy it so much -- and the human is a consenting adult.
In the less common cases of men with mares, ewes, sows, &c, it's hard to imagine they'd even feel it, much less find it painful.
Usually when slaughtering livestock, it usually done quickly and humanely as possible. And sustenance is a better trade off than sexual gratification.
If the sex causes neither harm nor distress to either party how is it worse than actually
killing the animal, humanely or otherwise? Then there's the well known environmental harm our meat industry causes.
How Meat Contributes to Global Warming: Scientific American
If either is to be condemned I should think it would be the latter.
Humans don't like being raped; they find it frightening, painful and horrific so it's logical to assume that it has a similar impact on animals, and you can gauge the impact of an action by how the animal responds to it and its resulting behavior afterwards..
No it's not. No-one's
taught the animals they should feel feel shamed or degraded by sex -- those are human inventions. To an animal "recipient" its just another strange interaction with those odd-looking ape things, like being brushed or shod.
And remember, most bestiality is the Fido on top variety. If they didn't like it they wouldn't do it (and I'm speaking of both parties
).
Read once about a guy who at a young age discovered he enjoyed raping animals, especially if he stabbed them as well. Would you consider that immoral?
Are you really serious? How is inflicting pain, suffering and harm in the same category as sex?
I'll ask you: If a man stabbed a woman during sex, would it be wrong? Why? (hint: it's not the sex
)
You don't see too many lions trying to frak a gazelle. When a lion kills and eats a gazelle it's natural but when the lion fraks the gazelle...well that's abnormal.
Same with people.
Back to this "natural/normal" thing again?
How many times do we need to go over this? Natural is morally irrelevant. Normal is both irrelevant, mercurial and culturally variable.