Eating pork was a sin because pigs are very dangerous animals for human health. A lot of viruses are supposedly were made because of people who farm pigs and ducks near each other. There are some lenghty explanation, but it basically turns their filth and fat into accidently perfect incubators. And even if people thousands years ago did not understand the exact process, they understood that people on pig farms were often sick.

There might be other explanations, but all of them default into "its actually dangerous" or "some guy disliked the taste/it was competing with his other farm animal". Or it might be "people are too fucking stupid to cook meat properly, so I am banning pig farming, because they are fucking retarded".