I just went back to check out TurnTable... and it looks like the "power-users" killed TurnTable. There is a link in the majority of the rooms like the below telling people what to play and what not to play. Freedom was the essential ingredient in TurnTable.
If you want an anything goes room you can always create your own. The Indie While You Work room has those rules because certain songs were becoming overplayed, and Nexting doesn't work there since most people are passive listeners (because they are working).
It does look like most rooms have several rules. As I remember, it became a norm. Mostly as a reaction from random users getting on the decks and playing absurd stuff to kill the room's vibe. We could call them trolls.
Edit: I clicked on the spreadsheet. Having a music black list is pretty extreme. I thought you were referring to room rules; like, only playing five songs then stepping down or having a list of who is up next.
Re: Trolls - on a meta/tangential note it does seem like "troll management" (aka moderation) could alternatively be called governance - it's essentially what keeps libertarian ideas in the fantasy realm - anything involving large numbers of people undoubtedly requires extensive rules in order to keep things stable (whether they're explicit rules as in managed systems, or implicit rules where avoidance of external authorities is what keeps people in line - ie, torrent culture).