I used to believe this too, but fediverse has also the goal or building communities, which is different than nostr focus on individual freedom (people become atomized individuals)

In a community some people won't mind having some of them having roles (specialization of role), and a role is the of a moderator.

Of course it would be better to allow a fine grain control and a member of the community would be able of reading content from instances the Moderator didn't allow (this means accepting Moderation is sometimes optional)