Its why lemmy lets users block a server now even though mastodon doesnt.

As someone who had to switch away from mastodon.art because my pool of federated instances was getting so small it felt pointless to be on a federated platform... I'm SO glad Lemmy takes this approach. I don't mind my instance having some control over who they federate with (I have zero interest in seeing actual nazi comment or CP for example) but if my instance blocked lemmy.world or another similarly large one I'd definitely be a bit screwed (mastodon.art defederated mastodon.social for a time!)