He has refused to own a cell phone since inception because he doesn't like the idea of having his movements tracked.
It's now well-known that most of the crypto we depend upon for cellular calls and messaging is broken and can be tapped easily. Seemless, real-time, local area SMS and call interception has been publicly demonstrated, and these demonstrations were not from nefarious or particularly well resourced groups, just keen nerds.
It's also been publicly demonstrated that someone can track your location down to cell tower granularity, from anywhere in the world, without permission, using just your cell phone #, without prior access to your phone, and with only commercially available network access.
And none of this even touches on the ticking timebomb of proprietary firmware in phones that is basically unsupported and untouched by manufacturers and networks from the moment you walk out of the shop. The opportunity to exploit vulnerabilities alone is mind-boggling.
Oh and the fact that most people are replacing all this with centralised messaging platforms like Snapchat, Facebook chat, and Whatsapp.
You're completely naive right now if you think every SMS you've ever sent, every call you ever made, and every location query you've ever put through Googles Location Service hasn't been logged or acquired by NSA.
And frankly, the idea that NSA or GCHQ can silently ring your phone and turn it in to a listening device doesn't sound so James Bond these days.