I can completely understand why they did but it really sucks that it had to happen. Hopefully, as the Fediverse grows, better tools are made available so instances don't need to defederate from each other.
With that said, I think it's a pretty amazing concept that they can. Terrible, sure, but nonetheless amazing.
I also wasn't aware that other instances vetted their users? This was the first one I picked. Is there a plan to address the issues beehaw brought up?