Good points, but I'm sorry to point out that buying the iPhone itself supports the war on general purpose computing. Jailbreaking might get you out of this set of digital handcuffs, but what about the next one, or the one after that?
I think the "war on general purpose computing" was a term coined by Doctorow (or Stallman?) and I have to agree with it in principle. I just can't go all the way and use a Longsoon-based MIPS device because of performance concerns.
It's not quite black and white. I can quite happily buy a PS4 (did you see the list of open-source software they used?) and still support the FSF and EFF as necessary.