I suppose its worth clearing something up. Off the shelf Android uses the same carrier messaging infrastructure that every mobile phone since like the 90s used. Apple is the one choosing a different route. I heard news that they were facing the law for blocking some SMS messaging by default, but I don't have that proof anymore. 

Yes you should still get as many people as possible to use Signal, SimpleX, or other verified highly e2e encrypted and ideally open source tools. SMS Is not a safe option IMO. Telegram and WhatsApp are not alternatives that actually respect your privacy and true e2e encryption because they comply with the laws of most countries as they currently stand.