Btw you are also free to block any instance yourself.

Not how the instance blocking feature works. it’s a common misconception because people don’t read the docs and just assume it does what they think it does. From the News Section on Join-Lemmy:

Users can now block instances. Similar to community blocks, it means that any posts from communities which are hosted on that instance are hidden. However the block doesn’t affect users from the blocked instance, their posts and comments can still be seen normally in other communities.

It’s not an alternative or replacement to defederation, not even close. I’m really surprised this misconception still persists even after widespread adoption of 0.19.x across the Lemmy network.