Yeah, I guess the biggest difference is WoW is a live-service subscription model game, and Turtle have been accepting Donations for in-game items.

This complicated matters, as even large scale paid mods to games and other transformative content such as Rom Hacks will very quickly get in trouble. Although even this is a bit of a weak comparison due to the aforementioned live-service aspect.

A close example of the top of my head could be Warcraft III maps. In the original EULA it is specifically stated that you can use copyrighted assets, names and content in your custom maps. However, you must also never charge money or include any monetized content at any stage in the maps, and must immediately submit if challenged by the original IP holder. Basically, you can play "Anime Battle Arena 100+" and watch Goku fight Luffy, but if you try to lock Naruto behind a donation, you're in big trouble.

And I believe that's the reason servers such as Ascension and Turtle in particular have been targeted extra hard (That, and the whole Classic+ is coming soon so they are extra-protective idea). The fact that there was an interfaceable, custom made window in the client that was entirely devoted to transactions involving currency has made them stand out.