Oh don't get me wrong. I don't want to use WhatsApp. I'm only on it at all because I need to speak with people who are using it without antagonising them. I still haven't granted it access to my contacts DB.

All three of Signal, Telegram and WhatsApp make me a bit off about using them for various reasons. None of them are what you'd call "user's privacy first".

As it is, I'm currently having occasional confidential chats (at someone else's request) on Telegram secret chats, and at least that probably is what it says it is.

I don't think any of these three apps are awful.

They are pretty slick, and useful.

I don't feel too bad actually using them, any more then using say MSN, Yahoo or Freenode.

They just don't meet the advertised bar of respecting individual privacy first. And I find that really misleading in the case of Signal and Telegram in particular, which emphasise the privacy angle, and then without letting you know, sprays everyone you ever interacted with outside Signal with a notification, including professional contacts, customer service agents, people you don't like, spammers, etc.