I propose we defederate no instance other than those with egregiously illegal content such as CP. Note that I know of no such instances.
As of the moment of this post, the only defederated instance is lemmygrad.ml, so voting Yea would refederate them. It's a genocide-denying Marxist instance.
Nay for now. While there's a few communities on lemmygrad that I want to see like Late Stage Capitalism, lemmygrad has been defederated since day one, and all of us (should) have known this when we joined, so there's no hurry to refederate with them.
The real solution is for Lemmy to let users block instances from their own view, then all the defederation discussions will be moot. When that happens, we should do as you proposed - federate as much as permitted by law.
I still think this is naive in the face of real information warfare. This feels like saying "Nazis are welcome here but they aren't allowed on the second floor so if you don't want to see them stick to that."
Eventually the Nazis will just drive everyone else away and take over the second floor as well. Because the Nazis have no such holdups about acting in good faith.
I believe that communities must take measures to actively protect themselves, particularly from those who would abuse a community's values in order to remake them. I don't think the abstract threat of slippery slopes rises to the real threat posed by those who continually demonstrate a proclivity for subterfuge and sabotage.
I should clarify. When the skinheads from the Nazi house down the street come over to visit, they must follow our instance-wide and community rules. This should be a basic fediquette for everyone. If they repeatedly fail to do that then we will have to defederate them. But if they check the swastika at the door and keep the Nazism to themselves while they're here, I don't see why not. Most of the calls for defederation so far have been about people not wanting to see activities happening on remote communities on certain instances.