I’ve seen the controversy where lemmy.world defederated from 2 piracy instances.
No they didn’t. They blocked 3 communities from 2 different instances. All other communities on those instances are available to .world users and .world is still available to all users on those two instances.
Blocking individual communities is not the same thing as defederating from those instances.
.world hasn’t defederated from either of these two instances. They’ve blocked .world users from accessing those 3 communities from .world. You, as a .world user can still access any community across those 2 instances, aside from the 3 mentioned. Any users on those instances can still access .world communities.