Device attestation is a way for a server to attest that a requester is e.g. an iPhone. Sure, it can be expanded to cover if the requester is, say, John Smith. But the server has to demand it.

Decentralized platforms tout not doing this stuff as a feature. You'd have to roll out the attestation system and require everyone running a web server to set up this attestation infrastructure; that is, the small guy running a model train forum on his laptop or whatever must risk prison time if he doesn't do attestation. That'd be so draconian that afaik not even China does it.