Beehaw has very strict moderation, like a traditional forum. They want a small, closed community where they can look out but nobody else can come in. (They’ve even mentioned they would switch to an allowlist if it could be made one-way.)

Lemmy.world and sh.itjust.works had easy sign-ups and Beehaw said the ease of sign-ups were responsible for a lot of trolls and bad actors. So Beehaw defederated from both those instances until they made sign-ups harder.