During the preconventional level of moral development , humans take developed our moral standard based on what the authority figures told us to. This tend to happen during our childhood, when our parents basically the one that determine what we should consider as right and wrong. (they will punish us if we behave in a way that they do not like)
This what make our moral judgement become self-centered. Since we only believe what our parents told us as absolute truth, we refuse the moral standard that is held by other people who were taught differently. But the truth is more complicated that that. Society's rule making process tend to be influenced by different cultures, religion , and personal experience that might vary between each individuals.
