We need to seen Kerry's complete military record, including the nomination forms for his awards, his medical records, and his request for curtailment based on three PHs. As a former naval officer and Vietnam veteran, I agree with the above analysis of Kerry's fitness reports.
It doesn't sound like Kerry's commanders rated him as even 'center mass', but lower. That makes him a pretty poor officer, and one his peers would try to encourage to get out before he embarrassed the Officer Corps. It is my understanding that commanders decide fairly quickly whether someone should stay in or not. It looks to me that decision was reached on the Gridley. And the Gridley's CO was right on the money.