Consider: self-hosting an instance requires a full-sized team of engineers, full-time, on an expensive server with plenty of resources, and many ways to be effectively DoS'ed offline, by anyone.
Matrix is meant to be "sold" to you as a "free, encrypted, federated, private self-hostable" chat network "like Discord but FOSS and full of cryptography."
They get this idea in your head, and the proponents - people who Absolutely Have Too Much Time, and are Linux Freaks Full Time - will sell you on this idea.
Then you try it out, and it shits on you. For any of a number of reasons - the UI screws up, you lose keys, the server software takes 3GB of RAM for accessing two rooms, you lose keys again, the client you thought was encrypting wasn't, the main client Element uses 4GB of RAM because it's a weighty Electron app, you lose your friend's keys, your server gets infiltrated by Nazis and/or internet abuse teams, gets DoS'ed, and so on.
It shits on you, because it's designed to. It is meant to discourage you from using the Free Cryptography Stuff and shove you back on Discord or other commercial technologies, where one Law Enforcement Letter can and will hand your DMs to fascists, bar none.
A month ago or earlier, I'd been called "insane" (ugh.) or "schizo" (are you a doctor?) for this line of thought - because they see me, and imagine newspapers-and-string conclusions being jumped to out of thin air.
Matrix just said the quiet part out loud.
Matrix does not want you using it, they want you acting like you do. They want people to use it who can afford to spring up an IT Tango Team and Ops Center for their app. Or they want you to pay to use their central services.
They want to discourage people from using Matrix for its original, intended purpose, because it runs against the values of the people giving them money and clientele (The police, intelligence communities, and national/homeland security/law enforcement agencies.)