There are a couple of posts that have studied your question. One involved the chemical makeup of "olive oil soap" which can be produced, but NOT by the body, under the conditions of the cleanse.
But here's the real kicker. If the body simply creates these stones out of the olive oil, and presumably, bile or other digestive substances, then why after many flushes do people stop passing these "stones?" Wouldn't the body just continue to pass the olive oil stones?
And why are some of the stones HARD, like rock? Olive oil, as you know, is NOT HARD!
And why have some reported having stones visible on an ultrasound, and then after flushing, the stones are gone?
And why have lab tests reported that the stones people are passing are made of cholesterol (NOT olive oil), as liver/gallbladder stones can be?
And why have the lab tests even conclusively stated that the stones are in fact gall/ liver stones ?
The question you raise IS a good one, and one that I thought as well. But there is a LOT of evidence to show that these stones are in fact from the liver/gallbladder.