I see it as healthy. Just as there is no simultaneous conversation about, say, walnuts in offline life, so there are multiple communities that discuss walnuts

I see it as healthy. Just as there is no simultaneous conversation about, say, walnuts in offline life, so there are multiple communities that discuss walnuts on boards with all the predicates and social constructs those communities have, from focuses towards, say, farming to environment to cooking, objective focuses, or social focuses in belief, location, language, of community. And no one's prevented from starting their own walnut focused board or even community. That Lemmys are choosing to not try to be super catch-alls from the start I see as healthy for communities. For search/discoverability, multiple boards each dedicated to walnuts may not aid discovery, especially in tails where signal is strong, perhaps oldskool directories/newskool directory of search/filtering could start to come in useful.