It makes no sense to me. You have by far the strongest military in the world. The USSR is gone. Ok, so there's China, but so far they have not made any seriously threatening moves. Who is left that is any threat?
The problem isn't so much the degree to which the threat is or isn't real. If they wanted to fabricate unreal threats, they could certainly do a better
The problem is that there exists a truly massive security-industrial complex. For example, a huge percentage of the population within commuting distance of Washington DC have some kind of security clearance, and their employment depends on it, it's part of their social group, etc. Often these people have lived a relatively sheltered "whitebread" life, except for commonly military service in some place like Iraq. Their biggest worry is that they'll accidentally be friends with someone who'll be busted for pot and that will complicate up their security paperwork for the rest of their life. Sadly, these people are hard-pressed to understand America's freedoms, having renounced much of it for themselves.
Large, highly profitable industries have arisen to service this part of the Federal budget. So they hire people and more people to fill more and more funded positions with names like "Analyst". They write papers which sometimes come out like this.
Personally, I think this is one of the stupidest, most short-sighted, bits of analysis I've ever read. But it's important to contemplate how these things emerge from a process in which most or all of the people involved consider themselves to be doing the right thing for their country, career, employer, social circuit, etc..