ohhhh ok yes I see what you mean now. inbox is where you do want the capability to pull all events tagged to you though. if you want to run a looser inbox, you allow more things, if you don't want that at all, you close it off. it's a gradient.
Discussion
yeah, it's partly on the users for setting inboxes to these spam party relays as well, and for the ongoing lack of actual outbox model implementation of several major clients (i'd say the latter is precedent and extremely boringly I TOLD YOU SO)