On their own accord. Your post implies that he is hyppocrite unless he gives you his property for no reason other than you demanded it. It's his animal, he has no obligation to give it to anyone, regardless of how legal it is to eat. Heck, not even animals. You can replace dog with any other object somebody may have. "Hey give me your ps4, or you are a hypocrite"
Like for the record, I am not advocating fro eating dogs. If anything I wish we could not eat any animals at all. I just find this particular point that if somebody thinks eating dogs is fine, they are obligated to give away their own dogs to first guy that asks. That's not how it works. He can believe eating dogs is ethical and still not want to give you shit. It's his shit, you are not entiteled to his shit. Regardless of how edible it is.