I assume you meant to type "requires", not "requites".
A dog requires nobody's consent to bite them, or even to pee on their carpet. He is not making a moral decision.
Should he choose to copulate with a human, he will not give a doggie damn whether the human dies of it, because caring is not part of his neural process any more than morality is. Same applies if he bites the guy's throat out. The dog is reacting to instinct.
Whether or not a dog or a dolphin humps someone is not a moral issue. It's about wiring.
A man, choosing to kill a fly, bite a dog or bonk a horse IS making a moral decision. The effect on the dog or horse is not the issue. The effect on the man is.
Bestiality is immoral if the majority of people think it is.
It will always be icky, even if only to me, but if the legally constituted courts of the land, Her Maj. Teh Queen, the Arch Bish of Canterbury and 50.1% of the British electorate tell me it's not immoral, then it won't be. In Britain.
Because morality is about decision making and nothing else.
What on earth does this have to do with morals, this has to do with intellect, and the ability to understand risks.
Your dog, cannot, simply via virtue of its wiring understand that the sexual encounter can, and often does lead to harm for one or both parties, you as a human can, so taking advantage of the fact that the animal cannot, is simply that, taking advantage of the animal.
And the bit about a dog not caring if it bites someone, that is some pretty odd logic. It is like your saying " So dog, you want to play the getting away with harm game , eh?".
If all of that is too esoteric for you think of the following analogy.
A gent at the bar asks for a cigarette, you give it to him, you both understand the risks of smoking, and the effect it would have, no one has done anything wrong. This is analogous to sex with an informed creature. It wants something, it understands the risks, and it gets something, even though harm is possible, it is understood.
Now, lets say this same gent asks you for a cigarette, you give him one laced with meth. Your still giving him what he believes he wants, but you are doing something totally immoral due to the fact that he has no idea that it is going to have a negative effect ( being high on meth.).
The dog is capable of asking for sex, but it has zero clue what it is asking for in regards to a human. It has no idea of the harm that can come to it, and beyond that, no mechanism for understanding this.
There is no ick factor here, i would have just as much of an issue with a dog fighter saying , " Well, dogs like to fight, so i let dogs fight.". Yes dogs do like to claim their territory, and keep it, but that doesn't mean it is okay to take advantage of this natural trait for our own enjoyment.