In what way hunting is the betrayal for the laws that Ralph and Piggy held dear?
Ralph and Piggy each concede the importance of food, but they have a priority list of sorts, and meat does not trump the need for fire watch, fresh water, and the day to day needs of the civilization. What Ralph and Piggy are getting upset about is that the hunters spend all their days hunting and then sleep the rest of the time instead of helping with the chores and operation of their camp. As the hunters become wilder and wilder we see that hunting is one way the hunters commune with their inner beastie and shy away from the customs and taboos of civilization. In painting their faces with blood and becoming "masked" they are "betraying" everything that Ralph and Piggy stand for: scientific thought, logic, reason, order...all that makes us civilized.