Wouldn't it make sense that chronic diarrhea causes weight loss? less calories are being absorbed if the food exits sooner, no?

Not necessarily: If the diarrhea is due to a issue with the colon, e.g., lactose intolerance, a person would not lose weight despite diarrhea. If the diarrhea is due to a pathology in the small intestine, then the person is more likely to lose weight. Wish you good health! - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. Get HPV vaccine

Not much: Most nutrients are rapidly absorbed in the upper intestintines. For a few days, diarrhea can result in weight loss, for the reason you state and because of the infection or other health problem causing the diarrhea. However, the body soon adjusts, with more efficient absorption of nutrients and more efficient matabolism. Diarrhea itself usually causes little or no weight loss.

Yes: Yes, chronic diarrhea may cause weight loss but it is unhealthy way of weight loss. It is not normal human physiology to have chronic diarrhea.

Yes: Not so much as exits sooner as poor absorption

Not particularly: There are people with irritable bowel syndrome that have daily diarrhea for years but maintain or even have trouble with excess weight gain. Nutrients are absorbed high in the digestive tract where poop is milkshake quality. The colon just extracts water as it passes to make it firm. Your simple idea assumes that the full length of the intestines does the same job, it does not.