The instructions in the FN seem to be phrased more broadly than the drill. I think you're fighting against the relatively clear import of the historical documents. I get it; like I said, I dug into these expecting to find that RX-97G was wrong, and that you were right. And I think you were/are right for somewhere between 75 and 90 years of the 1911's use. But I think, in the early days, at least among the cavalry, there was some expectation that their pistols would sometimes be carried hammer down on a loaded chamber. And that, per Hatcher, the Army subsequently figured out that playing around with the hammer wasn't such a great idea and that AD/ND's were more likely with that manual of arms than if soldiers/troopers just put the damn things on safe if they needed to be holstered with one in the chamber.
Which makes sense. The Army had a whole lot of things wrong going into WWI, just like every other major military in the world. Saying that there was an early period where they were recommending a sub-optimal approach isn't really a surprise. Heck, it took them decades more to teach a two-handed handgun/pistol firing grip.