It's a stupid majority.
Consider email as an example of a federated network: My name, email address, and text of my emails exist today on hundreds (thousands?) of different servers. If I decided I want to "delete" my name from the global email network, that's close to impossible.
The same would be true of a federated social network, but with a more intrusive and personal set of data. Users will not understand that they cannot delete their own mastodon toots (or whatever it calls them).
This is not how federation works. You can talk to any other node without having an account there.
Sure, your private messages may be delivered to your friends' nodes, but is this a big problem?
Toots are public by design. Everyone understands that and it has nothing to do with privacy.
It kinda depends on the content of those messages, doesn't it? In the context of this OP, if my messages are organising a genocide then yes it might be a pretty fricking big problem.
> Toots are public by design. Everyone understands that and it has nothing to do with privacy.
Says you. Most users will have been accustomed to centralized services where it is possible to delete a tweet and have it gone, unless somebody else has gone to special effort to archive it or screenshot or what-have-you.
I think a better idea is to force them to provide an API for interoperability, alternative clients and exporting the user data. Together with the federated social networks, it will change everything: https://the-federation.info.