Why is the elimination of feaces not an excretory process?​

Feaces is a product of egestion. It is not directly formed from the major organs responsible for excretion (liver, kidneys, lungs and skin) and hence is not a result of metabolic reactions. That is why, feaces are not an excretory product.

Explanation:

the abdomen (less formally called the belly, stomach, tummy or midriff) constitutes the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. the region occupied by the abdomen is termed the abdominal cavity. the stomach secretes acid and enzymes that digest food. ridges of muscle tissue called rugae line the stomach. the stomach muscles contract periodically, churning food to enhance digestion. the pyloric sphincter is a muscular valve that opens to allow food to pass from the stomach to the small intestine.

cell regulation is conducted by special proteins.