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.

What did he have to say about Matrix?

tbf how many people sign emails when they don’t work for a gov in any capacity and therefore aren’t likely a target.

people in this field tend go overboard with security when really nobody cares about what they have access to.