I really have a strong feeling that some folks have Stockholm syndrome or something.
If someone tried to sell whole iPhones assembled entirely from parts leaked from Apple's supply chain, it ought to seem obvious to anyone that this is wrong. Why is the principle any different when it's not an entire iPhone?
Why would it be any different for Apple?
Hmmm, I always wanted a Ferrari.
If you want a Ferrari, go buy one. They have quite long waiting lists from what I've heard.
edit: In order not to be completely off topic: Apple might have just the same problems with parts stolen from their suppliers but since every single iPhone needs to be activated, I'm very sure they would be able to catch "iPhones made entirely from stolen parts". So this is clearly not it. The fact that they don't sell anything will probably make this whole thing quite worse because if you could buy a genuine display for 250$ from Apple, why would you really buy from anyone else? That market would of course exist but it would be much much smaller.
I would not expect them to sell motherboards or for exampe face id sensors without some kind of pairing. But batteries and LCDs? Come on!
They are doing it just to stick it to anyone who wants to repair their device. Quite sad when you think about the origins of that company :-(
My guess is Apple started doing all this pairing stuff due to some security threat they saw before we did.
Apple does somewhat care about users privacy (I like that very much) but this is really not it. And it goes for the battery as well. And vibration motor. And rear facing camera. All these are just plain and simple middle finger to third party repair shops. You could argue about FaceID sensor and motherboard and I would agree with security concerns, but that's pretty much it.