> I'm sure there is no real end-to-end encryption.
"The audio/video contents of FaceTime calls are protected by end-to-end encryption, so no one but the sender and receiver can access them. Apple cannot decrypt the data."
You don't know what you don't know - or in other words, have you seen the latest research on iOS surveillance mechanisms? There could be other "undocumented" stuff that makes the encryption of Facetime Audio irrelevant.
In the very same doc you quote, they also say of iMessage:
"Apple does not log messages or attachments, and their contents are protected by end-to-end encryption so no one but the sender and receiver can access them. Apple cannot decrypt the data."
