The whole point of the first part of the book is Piggy wants to talk about his feelings and they kill him because they don't want to hear about his feelings.
They don't actively kill him because they don't want to hear his feelings. It's been a while since I've read the book, but I do believe Piggy, his glasses, and the conch represent order, reason and logic. If one reads Lord of the Flies in a literal sense, one would have a terrible read.
In reality, girls would JUST talk about their feelings.
In reality, a group of 6-12 year old kids would not kill each other, or even survive for so long in a foreign climate.