I can't say I see your point. Mind explaining?
My guess: The purpose of crying is to make people around you more likely to help you.
So if you don't have shoes, there is a chance that crying in public will make someone give you money to buy the shoes. But if there is a person without feet nearby, your chances become smaller, because people will redirect their limited altruist budgets to that other person. Your crying becomes less profitable.
Another monthly installment of the rationality quotes thread. The usual rules apply: