I don't agree with many points from that blog post, but I agree with your comment about phone numbers.

xx Messenger doesn't require user's phone number (it's optional, if the user wants to make it easier to be found by phone number).

Messaging clients on some other networks also don't require phone numbers, but that makes it harder to find people. xx Messenger allows the creation and use of network nicknames that can be ported to other apps.

Source code:

https://github.com/xxfoundation/elixxir-xx-Messenger-Android

https://github.com/xxfoundation/elixxir-xx-messenger-iOS

(Mobile app hasn't been updated for a while; the reason is development of a unified Web-based desktop and mobile client is going on here - https://github.com/xxfoundation/elixxir-speakeasy-web/tree/d... - and it may eventually replace xx Messenger).

xx Network allows 3rd party clients. There's an SDK - https://xx.network/developers-mixnet/ - to make that easier.

Disclosure: I own xx coins.

Not enough xs

Fourex sheathes (condoms)? - For that secure feeling?

or xxx Porn Rating?

The "I don't trust Signal" articles were one of the things that inspired me to push for making xxm first over other apps. Since then a few other options have also sprung up (Session, cwtch, simplex to name a few).

Also, it wasn't mentioned in the articles, but another issue solved by us and many of these other messengers is use of a private keyboard instead of the vendor/isp ones that can spy on users.

Unfortunately, I learned the hard way that better privacy and security will not beat convenience and network effects when you are competing with "free", so we are changing our approach.