Well he's incorrect in that we always had absolute privacy of thought. Its true we're no different from our predecessors who used cyphers, satire and concealment to communicate. It is also depressingly true that we are approaching a turning point in technology where our thoughts - from a purely technical aspect, may not remain private or even be fully our own.

https://en.wikipedia.org/wiki/Thought_identification

http://www.nature.com/news/brain-decoding-reading-minds-1.13...

I would argue this is the reason a bias toward privacy must exist, modeled after the same international conventions that outlaw use of WMD and torture.