It’s not just about lemm.ee, the up/down of federation is that stuff from lemm.ee gets copied to all the other federated instances and vice versa. So lemm.ee’s region aside, this move tries to help protect the fediverse at large by removing a major distribution hub. It’s not a full solution in that regard, but it makes a bad situation incrementally less bad. Other popular instances may end up doing this as well till better tools come about.