>I don't get the criticism?

There's really nothing to get since the criticism is subjective. I hold that opinion and I understand if other people feel differently.

>How is it difficult to do something new on nostr?

On your own? Not difficult.
Getting other parts of the ecoysystem to join you. Harder if you are not an infouencer with a large following. But I don't see how that related to the original topic.

>And what is wrong about being enthusiastic about an awesome protocol?

On its own? Nothing. The issue arises when that's practically all you see on nostr.