It's not selling physical hardware that binds Apple here; it's having an app store that requires the cooperation of national government to process payments. Pakistan could forbid Apple from opening Apple Stores in Pakistan, but Pakistanis would likely still be able to purchase apple products through resellers and/or black/graymarkets. And if iOS were not locked to Apple's authoritarian app store, oppressed ethnic minorities in Pakistan could distribute software through through their preexisting covert channels.