I think they just don't want to have to release such a document to the public, and probably for good reason.
Terrorists may gain a good overview of what we are doing.
That's definately possible, I contemplated such myself after hearing the news earlier today. Then again, most of the information they are presenting to the public is widely available through open source documentation.
In the end... If it's faulted, I see no reason not to discontinue it. I am sure those who should know, will still know what is going on.