This breakdown by @aurynn of the #RaspberryPi social media debacle clarified my understanding of how large-scale moderation can happen on Mastodon. https://eiara.nz/posts/2022/Dec/09/a-case-study-on-raspberry-pis-incident-on-the-fediverse/
In Mastodon there are two moderation actions you can apply to an instance (ignoring the "do not fetch images" thing): stop communicating with them entirely and stop showing any content from them to users, unless showing content to followers.
Do you think that it's useful to do the former instead of the latter in cases similar to this?