XMPP

I'm not a cryptographer, and so I can't really emit a judgement on the poster's abilities or reputation, but what's for sure is that this piece reads more like a bingo card of a person's favourite "crypto stuff" and how partially it overlaps with some characteristics of OMEMO, rather than a thorough and substantiated cryptanalysis of the protocol and its flaws for real-world usages and threats.

Some snarky remarks remarks like

OMEMO doesn’t attempt to provide even the vaguest rationale for its design choices, and appears to approach cryptography protocol specification with a care-free attitude.

are needlessly opinionated, inflammatory and unhelpful, and tell more about the author and their lack of due diligence (in reaching-out to people and reading past public discussions) than build a story of what the problem is, why it matters, and how to remediate it.

Don't get me wrong, I would love this piece to have been something else, and to reveal actual problems (which incidentally would have been a great boos to the author's credibility and fame, considering that OMEMO underwent several audits and assessments in the recent history, including by several state agencies in the German and French governments…), but here we are, with one more strongly opinionated piece of whatever on the internet, and no meat in it to make the world a better place.