There are a good number of criticisms popping up, which I am able to observe, like:

• use of Cloudflare, and Google and AWS servers for storage of messages
• non federation of use of Signal (I can partially see the point because of the mess XMPP has been for the past 2 decades, only handful clients are worth using, and Signal wants to be an app for masses that just works)
• Moxie’s attitude towards federation itself as a practice in FLOSS culture

Matrix, despite being technically federated, has almost all of its users on matrix.org server. This is what happens with federation usually. XMPP and IRC are free of people like Moxie, but also without reliable easy-to-use clients with E2EE, and without lack of grants and fundings like Signal got from Acton.

These are problems that go beyond fruitful conclusions, pushing for bipartisan choices between easy-to-use encrypted lock-in apps and sophisticated half-baked federated apps with hard to use E2EE.

XMPP community must work on creating strong easy to use PGP E2EE clients instead. Technical folks underestimate the power of simple UX in user adoption terms. (Not to mention marketing does not have any role, since Elon Crap and Snowden pushed for Signal and it got 50 million people in a week.)