A handful of the decade-based music communities on lemmy.world have been closed by their moderator @ptz@dubvee.org.
Sadly, the reason for this is because PTZ is also known as Admiral Patrick, the creator of the Tesseract Lemmy frontend that was just the center of a great deal of controversy for being found to have a stealth ban list of instances, communities, and users that he did not personally agree with. These bans are forced onto everyone who uses Tesseract, without their knowledge and cannot be turned off. In retaliation for being called out, a lot of the music communities here on lemmy.world were locked and labeled [closed].
In retaliation to that childish spite, I have launched my own music communities on lemmy.today:
I never actually used any of those communities. Was there really a need to have a different community for each decade of music? Is there that much activity? Knowing the size of the fediverse, I assume it would have been preferred to just focus on a single community called "/c/oldmusic" and require decade tags or something.