The Register failed in their due diligence by not clarifying from the beginning that this is a different Matrix chat than the open standard. They amended the mistake with an update to the post (quoted here in OP), but that is placed at the end of an article that not everybody is going to read all the way through.

IMHO this needs a rewrite to make clear from the outset that the Matrix protocol and matrix.org are not affiliated with the criminal chat service. As it stands, even with the correction, it looks like character assassination of a perfectly legal open source project.

Really makes me wonder why criminals won't use the actual Matrix protocol instead of this one. They wouldn't have to pay for its use.