Bergdahl walked off post.
The bad guys were captured.
Bergdahl is a soldier wearing the uniform of his country.
The bad guys are terrorists not wearing uniforms and not following the Laws of War, the Geneva Convention, or any recognized ROE. Therefore they aren't POWs. The 'enemy combatant' status was invented to fit the situation. Not civilian criminals who can be tried in civil court, but not military subject to, traditionally, military tribunals.
The conflict/war is not over, therefore talk of exchanging of prisoner/enemy combatants are premature.
The Administration has been getting hammered, even by the usually tame press on the left, by a loooong sequence of buffoonery - Ukraine/Crimea, VA scandal, etc, etc, etc.
Gitmo's closure was the very first Executive Order issued by the current Administration. Opportunity for a 'feel good' while showing decisive executive action to, finally, accomplish that EO.
Surprise - BOOM.
Not a word from this Administration regarding the Marine with rifles and a wrong turn in Mexico.
Or the civilian contractor (possibly CIA) imprisoned in Cuba for some years now. We do have more than a few convicted spies of Cuba's - including Americans convicted of such.
Or the now three Americans being held in North Korea. I hear the little fat one likes food and oil, yet nary a peep for any sort of deal there.
Sadly, we kid ourselves if we think the higher echelons of the USG won't write off a GI for their greater good - themselves. The bro network within the military won't, but those at the top of the slippery pyramid have and will.