People buy AP, which means they get more advantages in game. Making a "No AP Room" will ruin the spirit of the game because it would basically leave AP vs AP and no AP vs no AP stranded in their own rooms. What's the point of that? People mainly buy AP to destroy SOME default characters and to have fun. AP vs AP is exactly the same as no AP vs no AP.
Making a "No AP Room" would bring Aeria Games' profits down dramatically because people will stop buying AP... i mean what's the point? Everyone is equal anyway, why would someone waste money on something when the result is still going to be the same at the end of the day?