Pigs are classified as an animal meant for harvest, or basically livestock. Pigs fall nowhere near where dogs, cats, fish, or even a damned horse sit on the scale of what is classified as a pet. Yes even though we domesticated pigs that does not make them a pet. Cows are domesticated but you wouldn't have one running around your house.
So while some people (absolute mongletards) may have them as pets, pigs are livestock.