The issue is there’s no oversight here, or at the very least, no oversight that we can trust to be impartial.
When parties form a federation, it’s usually with a signed agreement, to maintain the integrity of the federation and keep it together. Shared standards, rules, ideals, regulations, etc. All I’m seeing here are parties trying to carve out a sub-federation, and with no neutral oversight, it’s just going to become a “people like me” circle.
And I guarantee at some point people are going to start thinking “Hey, if this instance isn’t subscribing to the shared blocklist, that must mean they want those other instances around, and therefore they deserve to be added to the list”
Then just like that, the fediverse has a defacto authority. Instead of one sepz, we have a council of them from the largest instances.