It seems to me that this is comparing apples and oranges. First, the human diet and genetic factors seem to be THE precipitating factor in stone formation. I have no idea if pigs have the genetic propensity for stone formation, OR the diet that would cause the stagnation of bile because of an abundance of cholesterol in the blood from the consumption of animal products.
But besides that point.....there are pictures of autopsied livers with intrahepatic stones lodged in the bile ducts. All you have to do is a google search of "intrahepatic stones". You'll get thousands of hits with many research and treatment sites. Doctors acknowledge their existance, but they don't seem to be opened to "flusing" them out with a large liver contraction caused by the consumption of an acid and a fat (like citrus juice and olive oil). Nevertheless, there are tons and tons of sites documenting human treatment for intrahepatic stones.