I’m sorry I have to spell this out for you, but in other parts of the world WhatsApp is The messenger. As in, since companies are easier to approach though it than, say email. Bundle that with the network effect, and it’s effectively self-ostracising to go without.

Having said that, I still do that, but I’m antisocial, and am okay with being excluded from group chats. But at least I don’t go around showcasing my ignorance/incomprehension at how other people do things differently.