In what way are the twins "seeing Ralph for the first time" before they all set off for the Castle Rock?

Ralph undergoes tremendous character changes throughout William Golding's harrowing novel Lord of the Flies. In the beginning, Ralph's confidence and use of the conch give him the appearance of leadership. This leadership seems to guide the boys along for a time, but without maturity or proper organization, this leadership is fragile.
After Simon's murder and the theft of Piggy's glasses, the twins finally see Ralph without his guise of leadership and certainty. Ralph has lost control of the boys, and any order the conch once provided died with Simon. For the first time, the twins see Ralph not as a smooth-talking leader of a capable camp but as a desperate kid.
In this moment, the twins surely realize Ralph never actually had any power. The power was in his followers, and his followers have moved on to Castle Rock.