She believed that the burial was a religious ceremony, and Creon did not have the power to deny Polynices that right. Antigone's strong beliefs eventually led her to her death by the hand of Creon. Never, though, did she stop defending what she thought was right. She is directly humiliating Creon by calling his opinions and decisions weak and unjust. She feels that Creon is abusing his power as king and dealing with her task to a personal level.
Man is the measure of all things.
Creon believes that the good of man comes before the gods. Setting the example using Polynices' body left unburied is a symbol of Creon's belief. No man who is his country's enemy shall call himself my friend. This quote shows that leaving the body unburied is done to show respect for Thebes. After all, how could the ruler of a city-state honor a man who attempted to invade and conquer his city.