The article is a weird mix, partially very relevant information [0], partially just saying "using XMPP without E2E encryption is… not E2E encrypted" which is a weird ting to get worked up about. Maybe I’m missing something here?

[0]: And honestly, something I have not thought about. I host my own XMPP server (Prosody) with only 2 accounts, mine and my wife’s, so it doesn’t affect me. But obviously you can’t expect everyone to just host their own server.