Kirby was really bred to be a PAO type, and by all accounts he was good at it. Some staff officers are top notch in their area, and it is a foolish boss who discards talent.
The new SecDef, Ashton B. Carter, is an odd bird.
http://en.wikipedia.org/wiki/Ashton_Carter
This leads me to suspect that there is some personal bad blood here. People you hate you fire immediately. People you think are wrong for the job you consider reassigning.
Harvard and Yale produce a lot of weird birds.