My point is you have to understand his principles first before calling him a hypocrite: in your cell phone example, the phone call he is making with someone else's phone is not depriving him of his freedom/privacy, but its owner's. He would likely advise and nudge the owner not to carry a cellphone for the owner's own benefit, in his capacity as an advocate, but if they have made the choice to carry one anyway, his use of someone else's cellphone for making a call is no different to him than utilizing a landline phone in his capacity as a user.
In fact, he has stated his principles/policies publicly and clearly, and someone posted it here as well. He never says "You are not supposed to use someone else's cellphone, but it's okay when I use it." That would make him a hypocrite.
Thus your example is a strawman here, with the implicit assumption that he has said "you ought not to use any cellphone" which he never said.
I think most misunderstandings of RMS come from the fact that people project on him what they think he would say and how he would act, not what he actually says and how he actually acts; while assuming he is merely some sort of activist engaging in civil disobedience and boycott, just trying to make a point and show the world a pure example of how to live. The way he should actually be thought of is he is fighting a war against people building proprietary software that, based on his theory, inevitably will lead to unjust power over users' lives through control over their devices. He is very pragmatic in that sense and willing to take any strategic advantage he can get in that fight, not deprive himself of that just to make a point. My understanding is at the beginning he used proprietary UNIX compilers to build GCC, for example.