Beehaw's defederation purpose is very clear, and they didn't start the drama. The mods of Beehaw started it as a safe space for minorities and marginalized communities, which is why you have to apply for an account there in the first place. The rapid expansion of the Fediverse led to their server being flooded with comments from other lemmy instances that the mods were trying to avoid by the creation of beehaw in the first place, so they chose to defederate. Seems pretty clear-cut to me.
Edit( The drama started when everyone else started flipping out, thinking they were owed participation in a community they weren't a part of. You are owed nothing)
If you don't like it, that's fine. They didn't do it for you. They did it for them and for their users. If you don't like it, you can create an account on an instance they still federate with.