The problem with this is that it isn’t really decentralized equally. Lemmy.world has most of the users and getting defederated from them is essentially a death sentence in terms of content and engagement.

Self-resolving issue here. If people hop away from LW due to LW making decisions they don't like, LW will cease being the one-go-to-place for stuff. Which is good, it shouldn't be. No one instance should be "the main instance". The right way to use federation is each person & community should make their home at a place where they vibe just right with the fed admins. It's even good for LW itself as it reduces the burden on its server and the workload for its admins.

Also also -- Defederation is a far more nuanced thing than just "is block". There is more than one tool that can be used by an ActivityPub admin.

If LW defederates from your home instance -- You can still manually follow communities that are in LW AND interact with them (unless the admins go out of their way to ALSO block USERS from your home instance), as "defederated from the instance" just removes it from the global timeline/global community search.

What happened here, though, wasn't defederation, it was a block, and a block on two specific communities, which outright prevents viewing & interacting with content from those communities from within LW. Which brings me to: LW's block on the piracy communities from dbzer0 doesn't stop LW users from interacting with dbzer0 as a whole. Or vice-versa. Only with stuff from the piracy coms.