Yeah, I hope it gets "fixed" at some point ("fixed" because I guess it is by design). For now, I created an account to most large Lemmy servers and subscribed to the magazine so future users find a fuller community :P
I see. Too bad, but hopefully this is something that may get fixed in a future ActivityPub protocol update (don't know if it is sth the applications can fix themselves)
So, I created a lemmy.world account just to subscribe and check if the federation now works. It works, but only for new posts, which is not ideal either. Hopefully federation can be fixed for older posts as well (I know that comments need someone from your instance to have subscribed to that community, but posts should always be visible to others)