The surgeon is probably correct for some but not all cases of gallstones. Some biliary problems are caused by a single one off event like an infection, virus, drugs, injury, etc; and once they are eradicated they can be gone for ever. Some conditions like "biliary sludge" can fluctuate and sometime disappear on their own without the invention of anything. However, the larger majority of gallstone problems are caused by inappropriate food, lifestyle, stress, being pregnant, the birth control pill, HRT etc. Consequently if you don't make lifestyle changes in conjunction with the Liver Cleansing they have every opportunity to form again.
The surgeon is in some way re-enforcing the philosophy of the forum but the story misses out the fact that stones can form even after the removal of the gallbladder because the origins of the problem lie in the liver.