The question is, are they generating enough content without that external source that it wasn't felt much? If that's the case, then it shouldn't matter. If it isn't, then people will leave and go to where the content is. Frankly speaking, my thought is that the federation should only be on as a backfill or last resort- if you're unable to generate content and discussion organically, import someone else's discussion.

Okay, but the same thing would have happened if they all joined Beehaw directly, or were spread out among many many instances. Part of Beehaw's logic was "Well, a disproportionate amount of moderation had to be done to lemmy.world so we defederated", but isn't that simply because there are more users on that particular instance? If, for example, we assume every single lemmy.world user joined separate instances and behaved the exact same way, would Beehaw have defederated all of their instances? If not, then the response wasn't the correct one, in my opinion. What happened is that Beehaw saw their mod work increasing, and nuked a large portion of their active userbase (federated users from non-Beehaw instances) to cut it down to try to maintain the culture they're trying to build. Unfortunately, I think all it will have done is throttled their growth and Beehaw will become an isolated instance with no large communities on its own, because the communities that were there (that lemmy.world was participating in) will just be recreated on different instances.