The list is available by clicking the 'Instances' link at the bottom.
https://sh.itjust.works/instances In there, there's a blocked section.

But that page doesn't tell you much by itself.

You can also check https://gui.fediseer.com/instances/detail/sh.itjust.works

It's gonna be the same list but it can include a reason and a bit more info.
I think it's easier to understand the format on fediseer than just looking at a list of domain names.

Defederation just breaks further updates and bans their communities, it doesn't technically remove the existing content from before defederation.

I've actually been purging some of the CSAM communities recently from instances that were blocked, but were technically still not 100% deleted on the server.

Let me know if you have questions or concerns or anything.

As for threads, that's a good question.
Personally, I'd rather not have Facebooklite in my lemmy feed, but I don't represent all users (nor even all admins for that matter).
Ultimately, TheDude has final say on anything, but I think this would be worth a discussion in the agora.

"Instances" at the bottom of the page will take you to a list of, I believe, federated instances, and at the very bottom, blocked instances.

Hoping they defed from them