In Minecraft creative mode, the creative menu works client-side. This means that when a player selects items from the creative menu and moves it to the toolbar, the server doesn't do an immediate check of the items. Consequently, the server has to do constant scans of player inventories to detect and remove illegal items (using plugins), such as command blocks/debug sticks ect, which could be used to lag the server. however this is not the big problem. this is fixed and playable. but...
A huge exploit arises with the use of spawn eggs, they contain 'Named Binary Tag' (NBT) data. NBT data itself is a standard game feature and is not bad when kept vanilla. However, various third-party programs and websites enable players to generate spawn eggs with 'custom' NBT data.
These custom-modified spawn eggs can then be spawned in a server via the player's hotbar (x+1,2,3,4 ect). Standard server inventory checks may not identify these items as bad because they just appear as regular spawn eggs, with the harmfull stuff hidden inside the NBT data. spawning of these spawn eggs containing harmfull NBT data COULD lead to severe server-wide problems. These include TPS lag, Insane bombs that will render any build useless, and COULD render the server entirely unplayable, like needing a complete rollback. The impact largely depends on the custom NBT and the intent of the player exploiting this oversight.
The challenge for creative server operators is the (current) inability to selectively approve (whitelist) specific, NBT data while blocking potentially harmful ones. (also the reason player heads glitch and stuff) This lack of control forces creative server operators into a difficult position: either disable NBT data altogether, which can limit vanilla creative gameplay features, or face the constant threat of exploits/destruction and lag. The latter option requires insane server maintenance, including time-consuming rollbacks to restore the server to a pre-incident state. (which will always happen so whats the point then)
As a result, many creative servers, including this one with a "anarchy" ruleset, have been forced to implement bans on NBT data to preserve server stability and protect the player experience.
Fixing this exploit would only be possible by Mojang (since the creative menu is client sided), through a future game update. This issue is not isolated to just 2b2d, it is a huge problem affecting ALL creative minecraft servers wether anarchy or not. thanks for understanding lol (please mojang fix).