In some of those countries, it’s not really a choice. Like, WhatsApp is the only way of contacting a company’s customer care (via chat bots that run on it), colleges and universities may have study groups on it and teachers may hand out notes etc in those groups, also apparently it’s also the only way to contact even some government agencies.
I know, I’m from those countries. Like I said, we used other IM apps before WhatsApp came along, and if something changes we can use a new app. WhatsApp currently leads the market due to the network effect, but it doesn’t have us ‘by the balls’.
(Though the most likely successor would be WeChat, which is arguably much much worse in many ways)
Do you require WhatsApp to contact certain government agencies? Do you require WhatsApp to get access to customer support? Do you require WhatsApp to get access to lecture notes? No? Then you’re not from one of those countries.