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.
My understanding from the beehaw defed is that more surgical moderation tools just don't exist right now (and likely won't for awhile unless the two Lemmy devs get some major help). Admins only really have a singular nuclear option to deal with other instances that aren't able to tackle the bot problem.
Personally I don't see defederating as a bad thing. People and instances are working through who they want to be in their social network. The well managed servers will eventually rise to the top with the bot infested and draconian ones eventually falling into irrelevance.
As a user this will result in some growing pains since Lemmy currently doesn't offer a way to migrate your account. Personally I already have 3 Lemmy accounts. A good app front end that minimizes the friction from account switching would greatly help these growing pains.