The actual issue is, that as an instance admin who had previously been in the loop for some time with #fediblock and other channels in which admins share this kind of info, folks expected him to already have disqordia blocked.

Also, it seems from his posts elsewhere that he actually was aware and didn’t care. Ample reason to defederate from .art’s perspective. (Firefish.social has subsequently silenced but not blocked disqordia)

All of this is relatively routine, the screenshot fabrication thing more unusual.

Defederation is an important tool and is part of what makes the fediverse work. In my experience, people who are strongly defederation averse are mostly either quite new to the fediverse or have the relative privilege of never having to really deal with bad actors especially en masse.