How do we know that Piggy is not fully aware of how far from "civilized behavior" Jack and his followers have degenerated?
The most intelligent of the castaways of William Golding's Lord of the Flies, Piggy nevertheless still believes that waving the conch shell in the face of Jack will somehow spare him from a brutal death at their hands. He and Ralph demand the return of the precious fire-starter--Piggy's broken glasses--from the bloodthirsty group with the innocent belief that because they belong to Piggy, then they should be returned. By nonchalantly entering the camp of their enemies who outnumber them in overwhelming numbers, Piggy and Ralph both show that the notion of civilized behavior is theirs and theirs alone. They should have realized that in Jack's mind, the only way he can completely control the others is by eliminating the elected leader, Ralph.
I would say that we see this in the fact that Piggy cannot (at the begining of the chapter) bring himself to admit that what happened to Simon was murder.
Piggy tries all kinds of things to try to avoid admitting this to himself. He says that maybe Simon is not really dead. He says that even if Simon really is dead that it was probably nothing but an accident.
If Piggy really understood how far Jack and his followers had descended, he probably would have been able to admit that Simon was dead and had been murdered.
Piggy in the book "The Lord of the Flies" is angry and upset that the tribe of boys ruled by Jack had stolen into their camp and taken his glasses. He knows he needs them and believes that by taking the conch with him that he will be able to still have an assembly;y called where he can clearly state his need for the glasses. He knows that the boys are bullies, but the reality of Simon's death and the whole drama played out during to the dance seemed more like an accident to him.
Piggy steps in when Ralph and Jack are fighting to speak under the pretense of gaining some degree of control and respect from the boys. He does not believe they are guilty of murder. He finds out all to late when he is hit by the boulder and the conch and Piggy are both destroyed.