lemm.ee told you the reason they were shutting down - not enough people to keep the place running and burnout. I can’t force you to see how minimizing and distributing responsibility helps those issues if you don’t want to. Less responsibility, easier for people not to ditch projects or end them.

Lemm.ee had the option to close their registration at any time. But registrations are only one source of user management.

In a scenario where Lemm.ee would have become a content instance, but kept their federation policy, they would still have received all the reports about posts on the communities they hosted, wherever the reported user comes from.

Lemm.ee was the instance with the most active communities after LW, there’s no way to avoid a certain level of responsibility.