Considering all communication is subject to eavesdropping the space they are wanting to access borders on the realm of private thoughts. And some day soon it just may exist in that realm.
Then contrast our potential inability to keep private thoughts with the fact that the government is allowed theirs by merely stamping Top Secret across a document.
https://www.youtube.com/watch?v=e-ZpsxnmmbE
CGP Grey has a very good explanation of this situation.