Everything Apple does in the name of security or privacy is about enforcing Apple's control over what you do with their hardware after you buy it. They give not one thin damn about your privacy: They want to know everything you're doing with your Apple hardware. Put a sniffer on your Mac and count the daemons phoning home to Apple. Your jaw will drop.

As to the supply chain issue, microsoldering is trivially easy for serious adversaries, as TFA suggests. Apple just wants that sweet revenue stream from people who drop their phones. That's what they're protecting.