Your OP is inaccurate because as others point out the Armys initial field manual procedure does not equal design intent.
I would like those who hold that position to show period documents showing the true design intent.
If you read the references I have cited, you will find the revisionist history is not supported.
No one creates a FM manual, and Operation Requirements Document, any document, in a vacuum. The Soldiers who wrote the 1913 manual would certainly had access to John Browning and the Officers who determined the tactics and doctrine of the day. I cannot prove that they did, but a couple of pages over is a line drawing of a prototype M1910, which indicates to me that the Logistics group were involved in testing and development.
The pre WWI Army was 98,000 men, half of whom were overseas.
http://www.spartacus.schoolnet.co.uk/USAarmy.htm That is a very small organization and I am confident that lines of access between Officers and organizations were short and personal. Heck, I expect everybody knew everyone.
In today’s world designers, testers, and users rub elbows through out the design, test, and fielding of new systems. What I see in these preWW1 documents is different format, but similiar processes. The same things were going on in 1905-1911, but at a much more personal level.
As for those who say, the Horse argument does not make sense, therefore it is bogus.
You are not a decision maker. You were not on the Smalls Arms Board making the Procurement Decisions for the US Army. This was an issue before the board, by a voting Board member. And because this was a Go-No-Go point for the Cavalry, John Browning included the thumb safety lock, for the reasons previously stated.
You want to carry your M1911 cocked and locked?. Well it is your decision, not original design intent, not SOP per the recollections of the Military here.
If you shoot yourself in the foot, it will be all because of you. John Browning did not make you carry your M1911 cocked and locked. The Army did not make you carry the thing with the grip safety deactivated. No one else made you do that. You did that on your own.
So stop twisting history to justify your actions