Historically it seems like pork is often restricted from the diet, I know that Ancient Egyptians, Jews, and Muslims prohibited its consumption at least, was this a thing and if so why?
You could consider crossposting this to /r/askTheology/, though it is not very active.
I apologize for not having the link, but there was an AskHistorians podcast that discussed this subject. The gist of it, as I recall, was that among the Semetic cultures of the near East, pigs were associated with refuse. People who ate pork were likely to be the poorest of the poor who didn't have the means to raise other livestock such as cattle. As such, refraining from eating pork was a means of placing one's self above an undesirable social status.