what data gets hogged back? most stuff can be turned off and are features that would be missing anyway from xmpp, like identity servers or integrations server. also you can selfhost your identity server and add integrations manually

Isn't like the entire point of Matrix that it's end to end encrypted, thus rendering any data servers acquire useless?

You could make the metadata argument, but having one node aware of even most transactions is better than having one node aware of all of them.