Which is pretty rich, because in the post where that quote originally appeared, the author recommended as an alternative to Signal a tool that wasn't even end-to-end encrypted by default.
You seem really hung up on that. A transient recommendation has very little to do with stated expectation that "a tool which claims to be secure [should] actually be secure".
(Matrix is very cool and I think it has a bright future as an IRC replacement and ultimately, perhaps, a Slack competitor --- something that provides opsec suitable for a commercial setting. I always come across as a Matrix hater in these threads, and I do not hate Matrix, and wish the project well.)
B) Matrix has always been very easy to set up E2E
C) Matrix is now E2E by default, at least with the client non-technical users will be using. I think it is for the other clients as well, but I do not know for sure.
Matrix was years from being E2E by default when this post, and that recommendation, was written.
It was still removed. Would it have been better to leave a note saying it had been? Yes. Nobody is perfect however.
> Matrix was years from being E2E by default when this post, and that recommendation, was written.
See point B from my other comment.
Edit: Add Would ... however.
Is it E2E for their other rooms? No.
Is it E2E for any usage of matrix they were going to be doing? Yes.
I also told them to be sure to hit that button if they did start any other rooms. None of them ever did, but they knew that they should if they cared about being secure.
Riot.im also did a good job of letting you know that it was unencrypted unless you hit that button.
Edit: What it boils down to, is that Matrix has been easy to set up E2E for as long as I can remember. It is also trivial to create a matrix account with no tie to your IRL self.