Look at their blog posts about PGP (one of them is pretty much "when I get a PGP-encrypted email it's always from a weirdo" - not any kind of technical argument, just a straight-up smear), or about Matrix.
Those comments were absolutely correct. That PGP failed as a viable solution for securing email communication isn't even debatable. And you're missing the point of the argument. It is a technical argument: The UX of PGP is so bad that hardly anyone bothered to use it, and that the workflow of decrypting the rare PGP-encrypted emails he received annoyed him.
