The Air Force is only blocking blog addresses ?

Personally, if I were to set policy for National Defense personnel, I'd block everything by default. People working in such a critical area should absolutely not have free access to the most dangerous information tool that has ever been invented.
That's good for when the soldiers get home. The rest of the time, they should be training, or guarding. Not posting on FaceBook.

Excellent, this nicely reminds them whom they are working for currently, and perhaps makes them think about what they are doing.