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.
I didn't even need to read the instance name. Only "Rule 1, 2" was enough to know this was from .ml. The admins there behave pretty much the same as Reddit admins; always fucking enforcing hidden rules. The link Blaze posted should show well enough which is the hidden rule in question.
Note that this is clearly done by the admins, not by some power-tripping mod. For example, one of the communities listed there (SNOOcalypse) has been locked down for a whole year, and the only mod there is my old account. (In fact one of the reasons I locked that comm down was because I wasn't willing to play along this shit.)