A lot of people are confused as to how someone like Bergdahl was promoted to sergeant (E-5) . He was generally thought by his comrades to be a loser as a soldier. He was thought by men in his platoon (44 men) and company (150 0dd men) to be self-obssessed, infantile, etc. As opposed to statements by enlisted men, statements or reports by commissiond officers about him cannot be relied on for verisimilitude. Officers are creatures wedded to career and are not inclined to write bad things about their men lest it reflect on them as well.
It is the policy of the US armed forces to promote people held as prisoners of war at the time their contemporaries are promoted without other considerations. This is a good policy and intended to avoid penalizing career people who otherwise would fall so far behind their contemporaries that they would have no choice but to leave the armed forces. pl