One other important thing about Jack is that on some level he understands the fear that is within the boys. Ralph thinks that having rules and meetings and structure will help the boys deal with their fear of the unknown. This and the sort of coolness the boys sense in him leads them to vote for him. Jack's first impression was one of the angry, dominant leader and the boys were at first putt off by it.
But Jack sees that the hunt and the kill and the celebration of it is something that the boys need, he understands that it allows them to externalize the fear of "the beast." He uses this fear to justify his actions and to compel the boys to follow his orders.
Ralph lacks this understanding and just keeps chasing the dream of being rescued even when the brief period of cohesion around a goal quickly begins to unravel in the face of the nameless, shifting fear of "the beast." His idea of a democratic, rule-based structure cannot survive in the face of that fear.