Why is the objective ethical ideal preferable to the subjective ethical ideal in interpersonal relationship?

An objective ethical ideal vs. a subjective ethical ideal discussion is an attempt to identify a more concrete or objectively truthful and honest ideal. A subjective ideal allows for a more liberal human interpretation based on perception, culture and emotional aspects. An objective ideal attempts to define without humanity a truth or optimum situation. If in a interpersonal relationship objective ideals are followed, then subjective ideals like being able to rationalize cheating or lying would be eliminated.