Beehaw is still federated with most servers, they're not isolated. There are a few that are defederated from for differences like allowing hate speech, but the two big ones were to ease up the moderation demands as they had open sign ups without captcha from what I recall. They were the source of a lot of spam and making moderation a headache. The admins plan to revisit the issue if better mod tools are developed, it's still a young platform and better tools could make it easier to moderate without cutting off whole servers.