Seems a bit of a catch twenty-two, to me.
If military employees take down information, it'll be seen as giving into the fear tactics that such terrorists are utilizing.
If military employees don't take down information, it'll offer assets to terrorists who may be planning smaller, personal attacks against individuals, or help them gather information to conduct larger-scale attacks.
Hell, I may be wrong, but, personally, I'd leave my information up. Granted, take down any and all information that may aid terrorists--don't go putting in, "went through the back door to the office today, told off Mike the security guard for falling asleep!" But this warning went out to soldiers, veterans and military personnel--these are soldiers, and individuals who are supporting them. Fighting is what they do, giving in and surrendering freedoms to the OPFOR is not.
Again, my inexperienced, potentially short-sighted perspective and opinion. But, there it is.