I don’t think they’re concerned that some deep secret is going to get out. They’re concerned that their communication is used for commercial purposes in a totally uncontrollable way.

And that might very well be exactly what OP is planning to do. They’re not asking us how to spend their time properly, they’re asking how to communicate with people on longer distance. Sometimes you need to let your friends know that the cooking class was cancelled or there’s a new club you all could join. Your friends are not aroud you all the time. Using apps like Whatsapp or Telegram is more efficient than calling each one separately and offers the possibility of group communication. It’s perfectly fine to use it for your friends group and it doesn’t mean you have no real life.

Yes, I don’t think we’re in disagreement here. I was just trying to tie it all to the beginning of the discussion.

OP’s asking about the kind of communication that is needed from time to time to, for example, arrange a real-life meeting. They’re not talking about social networks.

Yes, still the question “What are you doing with these people…” is not really relevant. OP’s responsible approach to privacy is not something that needs questioning.