I understood the Torah from an anthropological perspective to contain both theology (God's Law) and local Judaic customs (Man's Law.) Differentiating the two is difficult but I understood that the pig ban was originally due to health reasons (under cooked pork has a higher risk then other animals) and being a part of Man's Law would not have a specific divine intervention to teach them otherwise. It was folding in from Man's Law with the Torah and became interpreted as God's Law because it was part of the Torah.