Agree that it would be good to unite these communities. I raised it to the mod of the world community within a few days of the community being created but they deleted my post with not much explanation beyond "I'm not shutting the community down, don't advertise other communities".

This was also reported as an unmoderated community about a week ago, but the poster deleted their post. Not sure if the mod got in touch with them, an admin did, or they just randomly deleted it. I didn't notice any official public responses before the post got deleted.

It's certainly a decently sized community that's sufficiently under-moderated that multiple people think the mod is absent, and the existing mod doesn't seem to be putting up calls for others to join the mod team.

No, the communities will remain seperate, we have discussed already and there is no harm in having both