I disagree, they definitely don’t want their own mini Lemmy. They want a safe space they are happy with, and defederation the only way they can do that with Lemmy’s current mod tools.
Lemmy.world and sh.itjust.works make up about 20% of the acitve users in the threadiverse (source). That is a lot, and it sucks, but it’s far off from making beehaw an isolated instance.
Imo for now new users should be discouraged from joining Beehaw, lemmy.world, and sh.itjust.works, since all the content can be seen from other instances anyways.