That's because they defederated from the two largest competing instances. I'm talking about the communities users not the instances. The issue is that beehaw has the largest and therefore defacto default communities. The timing is bad and will likely affect wider adoption. The biggest problem is that it is entirely foreseeable and solved by either accepting a smaller community (closing signups) or improving moderation capabilities (getting more moderators or investing in an alternative moderation system) before it meant splitting the threadiverse in half.