Voluntary separation is better than enforced separation, but yes, I get where you're coming from.
The thing is, the entire reason - I assume - that there is a search for a new place to tweet / microblog is that there has been some intrusion or destabilisation of previous - perhaps unwitting - voluntary separation(s).
Whether this pseudo-volunteering was black communities keeping to certain, um, "places"(?; there has to be a better word; subjects? hashtags? keywords?) for community content, like-minded safe spaces and chat or whether it was merely other people respectfully (or otherwise) staying out of those places, I'm not entirely sure. Maybe a little of both?
Something was definitely going on for Black Twitter to have been the phenomenon it was after all.