Defederation is not the answer. Honestly, it's such a powerful and destructive tool that I question whether it should exist period.
Users should be treated like adults who are capable of determining by themselves what content they are comfortable with seeing.
If I don't want to see an extremist political community on my feed, I block that community myself. If an instance is full of such communities, I block that instance myself.
I don't want or need some other random on the internet to make judgement calls on what content I can or cannot interact with.
Defederation is a tactical nuke, that if used incorrectly will destroy the freedom, decentralization and openness of Lemmy, and replace it with a far more centralized series of walled gardens.
I fear that people are trying to recreate the reddit model on Lemmy.
Lemmy is not reddit,
Lemmy is better than reddit.
Reddit is top down, Lemmy is bottom up.
We don't need more mod control, we need more user control.
I would love to see more features built for user moderation of content.
Perhaps I could subscribe to another users blocklist, or follow their 'recommended communities'.
Instances themselves could maintain suggested block lists, and users could chose to enable or disable them at their own discretion.
I'm really not sure that defederation has any place at all. Even things like spam and bot instances I think would be better handled by a blocklist (enabled by default even), that users can turn on or off as they see fit.