Lord of the Flies does elicit an emotional response from the readers because they can connect to the characters. When Piggy is killed during his passionate speech about keeping order on the island, the reader does feel a keen sense of injustice about the senselessness of the violence and the waste of life. It made me angry to see the worst characters in the book, like Roger and Jack, triumph over the 'good guys.'
Golding's novel makes the reader root for the underdogs, like Simon and Piggy, so when they were killed in such a pointless way, the reader does become understandably frustrated. By the end of the novel, when Ralph is saved at the last minute by the naval officer, the reader feels an overwhelming sense of relief that the ordeal is finally over and the hero has been spared from the fate of "a stick sharpened at both ends."
At the same time, the abrupt ending was disappointing, because I really wanted to see Roger and Jack get their come-uppance and be punished. Golding never shows the aftermath of the boys' tragic stranding on the island and are left to imagine the details following their rescue.