I think the idea of WorldCoin is to have a “wallet” linked to a single physical person, then you can sign any work with your key, that you got by proving you are a real person.
IMHO, the coin part is just a hype element to get people to sign up for the password part.
As for ActivityPub, I don’t see how it helps with anything. An organization vouching for something, can already post it on their web, or if they want a distributed system, post it on IPFS.
“Give us all data about you… we’ll decide what to make out of it later”
What a deal! 🤦