Not exactly sure what you are talking about. People are fleeing from Whatsapp because it's owned by Facebook (which has one of the worst privacy reputations), because it's closed source and because facebook can replace your E2EE private key if they want so the E2EE is pretty useless. Facebook could also use the metadata if they want, which is pretty valuable.

Signal on the other hand is a nonprofit run by trusted people like Moxie Marlinspike, it's accessible to casual (non-IT) users as well (unlike XMPP) and it's fully open-source. It also minimizes metadata, like with the Sealed Sender functionality.

> trusted people like Moxie Marlinspike

Just out of curiosity and not challenging: what makes Moxie trustworthy?

His code. Go check it out and decide for yourself.

https://github.com/moxie0

So if someone can write good code they cannot be malicious? Not sure we are using the same definition of trustworthy.

Personally, I think that WhatsApp has an excellent user experience (including their encryption which is fine) and the only reason I am leaving is because of privacy concerns.

Signal also has an excellent user experience (much better than I was expecting) and most of the privacy concerns are alleviated. Decentralised would be better, but I have not found Matrix to be a particularly smooth experience.

I suppose this is a matter of opinion, but for many the worst feature of WhatsApp is the fact Facebook has access to most of your stuff and its E2E encryption barely worked.

Signal being centralized and tied to a phone number are design choices to make things easier for users. That's a far cry from the presumed reasons WhatsApp did things. The only reason that Signal has gained what traction it has is because of those features.

The problem is the lack of alternatives for non-technical people.

My grandmother can easily use WhatsApp or Signal.

People fleeing WhatsApp is basically fleeing from it because it is owned by Facebook. So it's usually for political reasons (especially in the USA) and/or for privacy concerns. A minority of tech-savvy users are leaving it for the reasons you say.