I don't understand it either but that doesn't lead me to leap to a conclusion that Apple's and Google's expert cryptographers and system architects don't know w

I don't understand it either but that doesn't lead me to leap to a conclusion that Apple's and Google's expert cryptographers and system architects don't know what they are doing. I instead blame my own current ignorance, and look forward to gaining more understanding. But yes as a user, personally I'd prefer to use and trust an app supplied by my OS provider, mandatory or not, built in to the OS or not (and plenty of Apple apps are optional after-the-fact downloads, so it need not be a forced download unless there are reasons for that that overcome all the negatives).