The dude who wrote this comment:

You have to give them credit, they kept their XMPP servers until the last. But you’re right that Google killed a lot of things.

https://killedbygoogle.com/

How Google killed XMPP

Google didn’t kill XMPP, it died on its own. XMPP still lacks default encryption and proper file transfers (there are 3 implementations of file transfers and all of them suck). The problem is that XMPP never had a normal protocol, and as a result, clients were forced to implement the features themselves through extensions which were not supported by all clients and servers. So it’s hard to blame Google for starting to do their own implementation of features. Matrix did everything better, but for some reason people don’t use it. They don’t, because there’s Telegram, Discord and so on.

Don’t defend XMMP. It’s obsolete. If you want a federation, use Matrix.