The problem is that (to use the comparisons given in the article) Nostr is a statically peered superpeer.
All the "downsides" of a superpeer (as the article says - "centralisation with extra steps") but without the benefit of dynamic peering thereby resulting in incomplete routing.
i.e. by its nature Nostr results in a fragmented network, which ends up looking very much like the federated network, albeit more interconnected.
Thats not necessarily a bad thing, but its a bit of a confused article, IMHO.
That's true. The hope is that users will favor generalist / unbiased relays (less fragmentation by design) rather than heavily biased / restricted ones. Maybe even fund them: I will pay you as long as you don't start banning large swathes of the network just because you don't like what they say.
Users you follow can also advertise relays behind the scenes, so it's more probable that, if you follow a coherent set of users, you will converge on a coherent subset of relays that doesn't really feel fragmented.