I tried that..twice, ditching Whatsapp, not easy, some friends/Family actually got pissed off by me telling them I wouldn't use it anymore, they refused to install other Apps.
See how engraved Facebook is in most of their lives, they have no idea what's being collected and how it influences them....just look at Brexit/US elections/Facebook-Cambridge Analytica.
As for the Topic, good on ya (Apple) to stick to it.
So just use SMS then, problem solved. If people dont hold a line, the stranglehold facebook has on communication wont ever end.