I used to see this on Reddit, I’m disappointed this behaviour is also on Lemmy.
Users collecting mod status on multiple communities, and then using that power to mass-ban a single user from a bunch of communities.
Modlog show how incredibly trigger happy some mods can be. Minor transgressions, deserving to have their comment removed at least, but then banned from unrelated communities as a consequence. This will only get worse as users become supermods.
Edit: It seems this is how an instance ban is reported, by banning from any communities the user has participated in. Then perhaps it isn’t all as bad as it seems.
This user was banned for being anti-Semitic and telling people to kill themselves. Also, when you’re instance-banned, you automatically get banned from the communities you were active in. The mod didn’t manually ban them from all those communities. When you attempt to post to a community in an instance you’re banned from that you weren’t active in, the instance-ban means the post won’t federate.