Why don't marine officers rate good conduct medal?

Answer 1

Marine Officers are expected to always conduct themselves in an appropriate fashion. If they do behave poorly then they are separated from the service whereas enlisted Marines may make mistakes and stay in depending on how bad the mistake was.

Answer 2

Marine officers do not rate the Good Conduct Medal because they are not eligible for the award. The Good Conduct Medal is awarded to enlisted service members who demonstrate exemplary behavior, efficiency, and fidelity during a specified period of service. Officers are evaluated on their performance through other means, such as fitness reports and commendations.