Earlier quoted context omitted.
A corollary to that lesson is to not support RCS. I'd have much rather iMessage only open up interoperability with E2EE platforms like signal or even Whatsapp (because Facebook is somehow the lesser evil in this corner of the privacy world).
In theory, E2EE is good until someone you are messaging turns on iCloud backup of messages you sent and now law enforcement can force Apple to give them your iCloud backup - with iMessage
I don’t worry (very much) that law enforcement will read my messages but I do worry that advertisers, insurance cartels, spam marketeers, bookmakers or price gougers will.