G-d wants us to restrain our behavior so we will be thinking of Him in all that we do. That sounds like a reasonable thing to do for the Creator of the universe. I gladly don't eat Pork. It is not a burden when you love G-d.
Because they would be giving up something they would have never eaten in those times. Dessert people are not going to raise an animal which needs water to keep cool, and wallow in it and muddy up their drinking water. At that time 99% of those people had never seen a pig.