Question for those more knowledgeable than I in this space: a huge value prop for iMessage is E2E encryption, correct? Why hasn't that gotten similar response from the AG? (OR has it already, and I may have missed it?)
As for Facebook, it is more likely because Facebook is in "progress" of enabling E2E and they have more users than Apple right now. It is easier to hit Facebook now than later unlike in the case of Apple that already implemented it from the start; it would go into court litigation for several years and most likely end up in Supreme Court.
Barr is just assuming FB will cave in.
PS: No, a huge value prop for iMessages is that it's built into iOS and any iPhone user can talk to another iPhone user, not because of E2E. Most users aren't aware of what E2E is.
Because when Apple was preparing it, it wasn’t public about it, and the then-sitting AG wasn't looking to generate news articles with his name that weren't attached to his role in acts fueling an imminent Presidential impeachment, so no similar warning note.