Why do lipase inhibitors not stop 100% of the fat from being absorbed?

Probably yes.: Lipase inhibitors are used to reduce the activity of lipases in the intestine to reduce fat absorption in the gut. They can have side effects like oily spotting, fecal inconsistence, flatus with discharge and abdominal cramping. Additionally, higher blood pressure, dry mouth, constipation, headache, and insomnia were reported. A malabsorption of fat soluble vitamins may develop. See comment.