That's all true, and at the same time does not invalidate the OPs argument.
You get to choose your phone platform. The implications there include whether or not you get exclusive access to Apple specific features like iMessage and FaceTime. They also include the cost of your existing collection of purchased apps and some DRMed media. You also have to pick your phone from the choices and features of the chosen platform's available devices.
You still have to choose "what you want" and then "Vote with your $CURRENCY." Your "wants" obviously include not just the OS/ecosystem design choices, but your financial investment into your incumbent platform, the convenience of sticking with what you know, your desires/requirements around screens and cameras.
You can totally trade off some of those other requirement over "platform security" or any other differences between iOS and Android. But don't fool yourself that you consider privacy to be critically important, if you're willing to forego it in favour of keeping your hundred or so bucks worth of Android apps or video subscriptions...