My first account on the fediverse was on Beehaw and I was happy with it, but defederating from two of the largest instances gave me a reason to find a new instance. Personally I understand and respect the decision -that is the point of the fediverse afterall.
They had a lot of good communities that will not be cut off from the fastest growing instances which will make things tough to rebuild I think.
The problem is that users on Beehaw also now can’t participate in communities hosted on those two instances. So for a lot of people, half their subscription feed is now dead with no warning. Unfortunately the defederation options at the moment are a bit “all or nothing”.