I was under the impression that this document exists to have -a- standard such that if followed before performing some sort of experiment whether directly tea related or not, you could more easily exclude preparation differences as a confounder when comparing results with people who'd also followed the document.

Certainly this is how the old coworker who had a paper copy pinned up behind their desk explained it to me, and that understanding was why they found its existence so amusing even if their preferred cuppa's preparation process was substantially different.

This could of course be entirely wrong but seeing the paper copy pinned to the wall always did make me smile.