Biting the hand that feeds is a natural instinct. Intelligence in those who must be fed is often underdeveloped in the immature and cannot distinguish between the food and the means of giving food and, of course, biting is a natural instinct to a hungry being. Sometimes beings consume the hand that feeds and the parts connected to that hand.
Eventually most beings get past the stage of biting the hand that feeds, although not all. Instincts to eat run deep, especially when hunger reigns. But hunger is different from greed and many human beings become overwhelmed by greed. They consume more than they require to the detriment of their health and their surroundings and they consume carelessly. They are careless in the manufacture of what they consume and careless in its consequences to themselves and their surroundings.
This carelessness and greed is the product of experience. Excessive consumption driven by desire and not want is the mature equivalent to biting the hand that feeds. As mature human beings we all bite the hand that feeds us.