It actually creates more confusion.It is a description of people who are members of Bandit and Brigand gangs and how they interact with each other.
<snip details>
Hope that clears up your confusion on how to understand the document.
First, because the details that I've snipped simply reiterate the point that I had already made, that in function and basic content it is no different from the 1977 MM.
Second, because the document doesn't say how the gangs interact with each other. For instance, it doesn't say how a village tough can fall in with a bandit or brigand gang (as opposed to, say, being thrashed within an inch of their life and then being sent on their way), or how much a merchant needs to pay a brigand lieutenant to be allowed to pass without being attacked, or other fairly typical interactions that bandits and brigands might engage in.
And suppose that there are 7 (ordinary) brigands in a group. The document tells me that, among brigands, "One lieutenant will be found for every 3 to 6 brigand in the gang." So the GM decides that this gang has two lieutenants. Now, the gang gets into a fight, and 5 of its members are killed or driven off; but both lieutenants survive. So now there are 2 ordinary brigands and 2 lieutenants. How does that fit with the specification of brigand organisation? And is a GM at liberty just to decide, when presenting a new group of brigands, that it has 4 members, 2 of whom are lieutenants?
Presumably the answer is that the ratios are guidelines, or generalisations of tendency. But are they based on demographic data? An intuition as to what makes for a good challenge? Something else? What should the GM have in mind in wondering whether to depart from them, and present the 4 member, 2 ordinary + 2 lieutenant, gang of brigands? Is this gang going to break the verisimilitude of the setting? Or just be tougher than its number would suggest to a player whose read the rules for brigand lieutenants?
From the document, and your post, it's not really clear to me.