Please. Captcha by default. Email domain filters. Auto-block federation from servers that don't respect. By default. Urgent.
And yes, to refute some comments, this publication is being upvoted by bots. A single computer was needed, not "thousands of dollars" spent.
Agree! Defederation is a nuclear option. The more we do it, the more we reduce the value of "the fediverse", and the more likely we are to kill this whole project.
I think defederation should only be a consideration if an instance is consistently, frequently becoming a problem for your instance over a large period of time. It's not a pre-emptive action.