It isn't hidden behind a curtain. It is stated up front. "There is no intentionality in this campaign; do what thou wilt." Everything is rolled randomly, every response is improv.I did not say I could not imagine that.
I am saying that you are making a distinction which does not exist, and which makes out that certain playstyles avoid doing something that cannot even in principle be avoided. EVERY playstyle contains significant, grounding intentionality. It is not possible to have anything even remotely like a "game" without that--and D&D is significantly more than the minimum required for something to be a game.
The idea that it is somehow possible to play an RPG, with a huge set of rules (written and unwritten), procedures (public and hidden), and principles (explicit and implicit), without having intentionality running through nearly every part thereof is simply ridiculous. Whether you keep the intentionality hidden behind a curtain or not, it's still there. By being a DM, running a game, you are an active creator of the experience. You cannot possibly not be. Fiction is creationist, and game-fiction doubly so, since you are creating both within the world and without.
How does that fit your thesis?