According to Sigmund Freud, the ID is a desire from birth for pleasure and life. The ID can drive every human to points which aren’t how they want to act originally, and perhaps they can appear evil. But humans don’t start out with this in their minds. From birth they only want to satisfy their needs, and when put in particularly desperate situations, it will change the human’s ability to think clearly, and even change their entire thought process from good to evil. As said in the source, “However, immediately satisfying these needs is not always realistic or even possible. If we were ruled entirely by the pleasure principle, we might find ourselves grabbing things we want out of other people's hands to satisfy our own cravings.”
From the start, humans do not intend to be evil. In LOTF these boys all came wanting only to survive and get off the island. They become savage due to their environment and the situation around them. Not one came to the island expecting to turn around