The underlined portion probably has a philosophical term that can be attached to it. That in itself probably means it's not important in the real world
. From a practical standpoint, what is useful, is. We have discussed at length that kata is a template from which techniques can be adapted to some several different applications with little or no modification. While the old masters may have had a particular application in mind, they would not have said that another school using the technique for the same or different application is wrong. In fact, they encouraged such flexibility. (quotes available).
Being flexible is one of the main teachings in combat at any level in most any age. This is why the Roman maniple was superior to the Greek phalanx and why some military aircraft are favored over others.
Strategy is based on several factors: Environment, capabilities, and normal human reaction. Sun Tsu said something like, "Feint to the east, attack from the west." Is this a valid idea
only for large Chinese armies? If a small French battalion used such a strategy, would he say the French major's application is wrong and not the true way? Even Musashi studied and no doubt adopted some of Sun Tsu's ideas. Strategists share a common body of knowledge.
A strategy is not owned by any one entity. It is equally valid in debate, sales, boxing, football, etc. The principles of gravity are equally true of apples, rocks and spaceships. MA principles are like this. They are all designed for use against another human (most of whom have similar natural reactions to stimuli) and employ the same general biomechanics.
Like you, I understand Chris' point and his absolutism in the true Way of his particular style. It can be useful in its preservation as it currently exists. With respect to Chris and his extensive knowledge in his area of expertise however, such absolutism and strict fundamentalism in anything denies the existence of other thinking, including by the one who wrote about the subject! and there is risk of interpreting it in a too narrow view.
There is more to anyone's thinking on a subject than can be written in a short manuscript. There may be thoughts unwritten that could influence its interpretation or being seen in a broader scope.
This is why I take a less rigorous view of Musashi's book, just as I do the Bible, and have no reservations of extracting lessons from them, even though I am not a swordsman of that school nor a Christian.