I get that point of data actually being kept at one point, but other server can also save that data if the POC service makes a point to signal other servers (That's the whole point actually).
But what about the auth data? What if the POC service deletes then how does the other servers authenticate that user since the POC service is not there anymore, maybe I am not getting the auth part yet for Fediverse.
Hosting a website with an RSS feed is federated. It doesn't solve the problem of finding interesting RSS feeds unless maybe RSS aggregator feeds exist (which they probably do).
Bluesky -> not actually properly disintermediated or federated. mastadon -> equally misleading.
Bluesky host and manage centralized infrastructure that would break the system if turned off.
If an owner of a mastadon server deletes their server all the connected users profiles get deleted too.