The open signups is the sticking point. Even at the point of de-federation, Lemmy.world was a respectable community and still is today (even if it's shitpost city for beans atm)
The admins here aim to curate an explicitly friendly space to chat, and they intend to achieve that through extensive manual review. They've also posted an article about how if you let even a small amount of toxicity through, you quickly lose your nicest and friendliest members of the community.
I think what they are waiting on is A) a more granular ability to allowlist or blocklist communities on specific servers, B) enforce a manually reviewed application for users on other instances to post on Beehaw, C) Allow only one-way posting but two-way reading.
See this comment and see Lemmy isues #3255 and #3275