That last paragraph may have read like I'm tapdancing around reality, but I think it's a coherent and clear position. It's also one shared by many in the scientific community, including cosmologist Stephen Hawking, who has mused many times on the matter. In a speech entitled "Life in the Universe" Hawking says: "What are the chances that we will encounter some alien form of life, as we explore the galaxy. If the argument about the time scale for the appearance of life on Earth is correct, there ought to be many other stars, whose planets have life on them. Some of these stellar systems could have formed 5 billion years before the Earth. So why is the galaxy not crawling with self designing mechanical or biological life forms? Why hasn't the Earth been visited, and even colonised. I discount suggestions that UFO's contain beings from outer space. I think any visits by aliens, would be much more obvious, and probably also, much more unpleasant."
Hawking goes on to state, "Maybe the probability of life spontaneously appearing is so low, that Earth is the only planet in the galaxy, or in the observable universe, in which it happened. Another possibility is that there was a reasonable probability of forming self-reproducing systems, like cells, but that most of these forms of life did not evolve intelligence."
With the acceptance that actual alien visitations are an exceedingly low probability, what truth then is contained within these declassified documents? I think the answer is much more terrestrial. In looking at these documents, we're inspecting trees and trying to guess what kind of forest they comprise. There's no need to look across the known universe into the unknown universe to find it. We need to look only at the post-war political climate.
Although the USSR and the USA were allied against Germany and the Axis powers during World War II, they were only united by common enemies. After the second world war ended, the Cold War began. Germany was divided into territories managed by the Americans, the Soviets, the British and the French. Berlin itself was divided into different zones. The documents I reference in this blog post are from that post-war era, where former allies were trying to decide if they would become enemies or remain mere rivals. That decision-making process lasted for decades.
The Central Intelligence Agency played an important role during the Cold War. In many ways, it was at the vanguard of the chilly conflict. In a war that was entirely fought through proxies and through information campaigns, misinformation was a powerful weapon. A cheap and effective way of creating just enough uncertainty in a rival to prevent, or at least postpone, action. If one were to, say, manufacture an extraordinary event where eyewitnesses observed a display of extremely advanced technology, and then arrange for that event to be covered in the local papers, it would most certainly end up on the radars of rivals. And if one of the eyewitnesses was the former mayor of Gleimershausen, it would have to be at least moderately credible. Enough to postpone action.