What does piggy think the boys wanted when the attacked them in the camp? Why he think this?

Piggy thinks the boys wanted the conch. The conch simply does not mean anything to Jack and his followers anymore. It is a symbol of Ralph's leadership that is now dead. The conch stood for democracy, dignity, and civilized consensus. These ideas were the opposite of what Jack wanted. Jack was able to effectively connect Ralph, the conch and Piggy with weakness. The conch only means something to Piggy. He cradles it and misinterprets its importance.