it doesn't explicitly forbdit it. It just doesn't spec it out, because it doesn't need it for the protocol to work. There are already many relays and clients that do just this.

I think GP's point (which I agree with) is that the functionality is almost essential. When it's not part of the spec, then you end up with differing off-spec implementations, and again, centralization risk.

This would be like the HTTP protocol not defining `POST`, and leaving it up to servers and clients to implement it based on however it feels like.

I really like the ideals behind Nostr, but I think its implementation and execution could be better.