Ah, well in that case, the parent poster can just say that asking about the cause of the creator is a valid thing to talk about, because they mean a subtly different kind of ‘cause’ than the kind of cause you told them wasn’t valid to talk about outside of the universe.
They can, but that wouldn't be too interesting to anyone in this universe. Or that it how I read it. Just like a being in a game wondering what caused the game company/programmer to write the game..
The reason will have no consequence to the beings in the game, and thus they will only be interested in the causuality mechanism within the game..
I infer then that you think the concept of a creator outside of our universe who caused it is a concept of no consequence. If so, then on that we agree.