I grant the premise that Unity sucks and has made changes that make it much harder to be an indie developer using its runtime.
That said, I don't understand the decision to shut the group and encourage members to move to a more general game dev group instead. If the reason is "everyone stopped using Unity, we don't have any members" then I understand, but the press release didn't say that. In fact it implied there might be thousands of members.
The closest thing to a reason they gave was that Unity has become hostile to indie devs. But Unity doesn't run BUG, so if some people are still using Unity, which I assume is the case, wouldn't they still benefit from having a users group? If it's an act of protest by the group organizers, that seems annoying for the people who still use Unity and got value out of having access to that community.
Without sufficient context to understand the decision, I find I'm not sure what this act accomplishes, or what it intended to accomplish.