From the very beginning of the novel Lord of the Flies, by William Golding, Piggy is treated like an outcast. Though he is the character who demonstrates the best intellect, reasoning, and leadership, he is ignored, ridiculed, and eventually even killed because the other boys simply do not like him or want to hear what he has to say.
Ralph is the first to meet Piggy, and he does everything he can to distance himself from him. Piggy is not a pleasant-looking boy, and immediately Ralph tries to leave Piggy behind.
"The naked crooks of his knees were plump, caught and scratched by thorns. He bent down, removed the thorns carefully, and turned around. He was shorter than the fair boy [Ralph] and very fat."
Piggy is wearing a windbreaker and thick spectacles (glasses). One of the first things he has to do is excuse himself, in his rather whiny voice, to go to the bathroom several times because he is having diarrhea from eating too much fruit. Between his appearance, his grunting bathroom noises, and his shortness of breath from asthma, the fair and fit Ralph wants nothing to do with this overweight, bespectacled boy.
To make matters worse, Piggy reveals that he was brought up as a rather spoiled and pampered child by his "auntie" (his parents are dead), and she has tried to shelter him from doing too much physical activity. Piggy is a sharp contrast to Ralph who stands on his head when he is happy and likes to do physical things.
Though Piggy does seem to understand the need for order and organization, no one wants to listen to his ideas. Once all the boys have gathered, he is virtually ignored until Ralph reveals Piggy's name. Then the boys, especially Jack, begin taunting him mercilessly. Even when it has been decided that whoever has the conch gets to speak without interruption, Piggy is interrupted and ridiculed. Despite his apparent uselessness, Piggy (through the use of his glasses) provides fire--a means of survival and potential rescue--for the tribe.
Later we read that Piggy is the only boy on the entire island who does not get tan, that Jack resents providing the fat boy with meat, and the hunters steal Piggy's glasses to make fire.
These are all very young schoolboys, and it is clear that they offer their allegiance to whoever looks like the best leader, regardless of his leadership skills. This is evidenced by the fact that the boys choose Ralph to be their leader despite the fact that Piggy demonstrates better leadership qualities.
In the end, Piggy the thinker is deliberately killed because the savage boys no longer want to hear what he has to say.
I'm only a junior in high school, but a few reasons the boys are mean to Piggy are because of his physical appearance. All the other boys are lean, and mostly attractive young men. Piggy isn't. He's big, and has glasses, and that would make him a target anywhere. Even in modern day schools.
Another reason that the boys are so mean to Piggy is because of how smart he is. In the Lord of the Flies you can see the 'reverse utopia' and these 'sophisticated' boys are coming from an English school, and they've now crashed on paradise with no leaders or parents to tell them what to do. The last thing that they want to do is have someone bossing them around, especially someone like Piggy. So when Piggy suggests things, such as making the clock, they all blow him off. Piggy represents intellect, and in an uncivilized society you can't have intelliect. Therefore, Piggy must go.
Hope I helped. :)
Lord of the Flies