eating pigs back in the day gave you bad parasites. cooking things thoroughly isnt even done today, so its no surprise it might have been worked into the 'rules' of a religion.
interesting fact:the medical symbol,the caduceus, which is really old, is actually parasites (guinea worm i think?) wrapped around a rod. back in the day, this type of parasite you wrapped around a rod to pull it out, turning it a little more every couple hours, if it broke, it could kill you, through toxins causing elephantitus and clogging blood flow. early medicine. yummy. i dont know what the wings represent. doing it fast?(or would that be bunny feet? wait, thats luck.../shrug)
moral: parasites are bad for the congregation, parasites can come from poorly cooked swine, swine is the devil. say no to pork in anceint times.