Banning piracy? Like the mere encouragement or?

Just the mere encouragement & discussion, yes. The banned communities do not allow direct links to pirated content ([email protected] has a rule forbidding that).

It’s strange to see people saying there was some sort of legit reasoning, the lemmy.world admins did not receive any sort of legal DMCA/NTD request or anything of the sort. They were simply trolled hard by a brand new account from lemm.ee asking to defederate from “piracy” communities and lemmy.world admins took the bait. See the post yourself lemmy.world/post/3175920

Incidentally that same user has created troll accounts at other instances & have been getting themselves banned, they were already banned at the dbzer0 instance so it looks like it was simple retaliation to attempt to trick other instances into defederating/blocking them.