To some people, animals are people.

Thus, to own an animal is to own a person.

If you knew a product was made with slave labor, would you want it?

If it was made from the corpses or body-fluids of enslaved beings, would you want it? Or would it be immoral?

I think it's a battle that shan't be won, for we must eat something, and all beings, plant, insect, mammal, or fungus, or anything else, they all have a will to live.

To violate a being's desire to live is normal.

It's normal to eat living things, so I don't think this issue means very much, except that people are ok with violating other people's moral codes, as well as ok with enslaving intelligent animals, as long as they are less intelligent than a human.