The problem is threatening the whole Fediverse
(...)
This is a grave abuse of the protocol: messages are silently dropped. It stands against everything the Fediverse is trying to do: allow users to communicate. My experience with open protocols allows me to say that it is a critical problem and that it cannot be tolerated. Would you settle for a mail provider which silently drop all emails you receive if they contain the letter "P"?

Oh, the drama. I think this is a wrong take. The point of ActivityPub is not that we all see everything. Is so the servers can exchange activities. But whether it makes sense to put it in our inboxes or not, depends on what particular application is supposed to do. If using AP would require the application to show everything, what would be the differences between the apps?

I use Threadiverse because I prefer a bit more structured content than what's happening on Mastodon. While I would love to be able to follow the few accounts and tags on Mastodon that interest me, the fact that I don't see all that traffic is not an abuse of the protocol

Also, correct me if I'm wrong, since

Pixelfed is designed to mimic Instagram

Then what Pixelfed does is also correct, Instagram also does not show the whole wall from Facebook. Only the pictures, right?