I disagree with the OP but that's a bit of a non-question. I was under the impression that the motive for any sort of publicity stunt is trying to gain publicity..
Trying to portray a message of transparency after few years ago being exposed by Snowden for running a non constitutional spying program on all US (and non US) citizens.
I thought the motive for positive publicity from the DoD since that happened would be pretty obvious.