It would be an expensive service to onboard people to nostr. As soon as people would use their damus account on FreeDamus (web version or so), Apple would probably ban even a moderated Damus and all apps that use the nostr network.
Discussion
I wonder if it has to grow bigger as web app clients before getting into native iOS.
Lots of techs don’t have these mod requirements or demands that a platform ban users who create objectionable content.
eg email, all private messaging apps, etc.
They have judged Damus as a platform, whereas in reality it doesn’t host anything.