Note that this is a long article and this is but one short section of it. Most of the analysis section deals with mindset related topics.
I think a key issue that could be examined a little more is the oft repeated dictum that "distance favors the good guy".
This author is questioning that. But apart from some of his mistakes in characterizing CQB with a carbine, what about that rule of thumb?
If the attacker draws a small pistol and there is time or opportunity to create distance the dictum seems to hold in general.
If the attacker begins to unlimber a rifle, and there is an opportunity for any movement at all; would closing the distance with precision fire be more appropriate?
I thought that is what the author was driving at.