This is not so much an “ActivityPub problem” as it is just how things work when you move something from point A to point B. You can’t unsend an email (or physical mail) or untell a secret.
The idea that you can just delete something on a whim is an illusion created by the centralized silo networks, and it’s not even true those cases as it’s generally a soft delete, and archived by other means anyway.
This is not so much an “ActivityPub problem” as it is just how things work when you move something from point A to point B. You can’t unsend an email (or physical mail) or untell a secret.
The idea that you can just delete something on a whim is an illusion created by the centralized silo networks, and it’s not even true those cases as it’s generally a soft delete, and archived by other means anyway.