This isn't just limited to communications tools. For example, people might have dietary restrictions for non-health reasons (religion, environmental impact, etc) that others do not share or even understand. I don't mind accommodating those (to a limit) e.g. when picking a place to eat, but it is a burden placed on people around them. That's just the way it is, I guess, and I suppose all people can do is try to minimise the burden, and to be accepting of those placed upon you.
They create a burden without reason.
If it helps, you can try visualizing it as a fully connected graph that initially has equally weighted edges between all nodes. But then the weight of all edges connected to one specific node goes up by multiple factors. That node loses out much more than all the other nodes.
I personally rather observe various groups in society with very different kinds of preferences.
Your signal: I don't care enough about our communication to use WhatsApp, because of reasons that are obscure to 99% outside a tech community. Similarly, they don't bother to reach out to you on other communication channels, because they don't bother enough.
The important thing to understand is, from your communication partners point of view, you create a burden without reason, so they work around it in (their) most effective way.
I've been there and didn't support this or that messenger. By now I think, the only way to solve those kind of issues are i) sane laws that regulate privacy and communication security, and ii) trends that create a need for a new communication style - private, secure, and human (like, calling from time to time, find a better solution to ghosting, things like that).
I'm convinced that we need positive incentives for that, instead of creating artificial burden.