Jack claims that Simon is the beastie; he implies that the boys' blood lust has a hint of hidden truth. Of course, Jack is the one whose blood lust is so savagely alluring that it is almost addictive. It is Jack, who has the ability to convince the boys that the beastie is Simon and that the blood lust is the proper way of acting in a situation. He is further able to manipulate the boys to obey him whether it is hunting, or electing a leader to be feared or loved. What do you think?
Whenever people are fearful, they often turn to those who will issue brute force against what is perceived as the enemy or threat. History is replete with examples of how many times a weak, fearful people will put their faith in a dictator; or incidents in which people of a community in the old West (of the U.S.) allowed posses to form and ride out to hang the men who threatened the safety of the community. Many times people revert to the simple rule of the strong over the weak, with strength perceived as brute force.
This conflict is what takes place in "Lord of the Flies." The remnants of society have been torn from Jack and eroded in Roger, whose behavior has been controlled only by rigid rules of society. Once Jack and Roger are removed long enough from society's limits, their behavior reverts to savagery and evil. On the other hand, Ralph and Piggy are more rational and seek to reason things out rather than use brute force against antagonists or threats. But, even Ralph waivers, having participated in the pig hunt himself. Their faith diminshed in Ralph, fear of the beastie and even of Jack grips the boys, and they follow him. After he steals the fire, Jack becomes the leader because he has the key to their being saved. Only Piggy holds steadfastly to reason, although it cannot save him against the brute force of Jack and the others. Only Simon is intuitive, but is killed because of it as Jack and the others recognize the power of his spirituality as the soul of the group; once he dies, anarchy rules. Sam and Eric are beaten until they join the hunters. Fearfully, they tell Ralph that they cannot help him because Jack will have them beaten. So, Ralph must hide, hoping the hunters will not find him; however, the island is ignited to burn him out.
It is only the naval officer as a deus ex machina who saves Ralph for rarely can rampant evil be stopped. The evil in the heart of man has so taken over Jack that he abruptly halts in his fleeing from the hunters when he sees the vision of society, and stands immobile. As Ralph and the boys weep, understanding their "end of innocence" and "the darkness of man's heart," the officer is "moved and a little embarrassed." So he turns away and lets his eyes, ironically, "rest on the trim cruiser [battleship] in the distance.
Jack has led the boys down a path of violence, savagery, and the "darkness of man's heart which is the 'beastie'." There is no real return home, for they are greatly changed by the evil they have harbored on the island. Besides that, their country is in the midst of a brutal conflict itself: World War II.
I think that when the boys are afraid, Jack's power increases. Jack is the one who controls the hunters and the hunters are the ones who seem like an army -- they are the ones who seem capable of violence.
So if they are capable of violence, the boys are more likely to give Jack power when they are afraid because they think his group can protect them by using violence against the beast.
Jack uses the beastie and fear to enhance his influence over the boys, simply for power. Jack is a charismatic leader, always in control over everything around him. He is the embodiment of greed and evil that lurks within every human, and gaining power makes him all the more powerful.
Jack is able to control them because he feeds on their own fears. He also persuades them to consider Simon as the beastie, because Simon is so much weaker than anyone else.