Alice Springs and the nearby area known as Pine Gap are not the source of all the Pine Gap gossip. The real installation is on the western coast of Australia. A common ploy, when trying to avoid scrutiny, is to point to a place other than where the action is. Thus, there is the Pine Gap of record and the real installation, which is not anywhere near where the public might come and gawk. As with all CIA installations on foreign soil, the true nature of activities at this installation has always been denied. Given the desolate area, lack of nearby vantage points, and sparse population, it is well protected from prying eyes. Thus the most sensitive activities have taken place there - research into the biology and psychology of alien visitors and to a minor degree the physics of their technology. The goal was to treat the alien presence in the same manner the CIA has treated governments, corporations, associations or individuals it did not control and deemed a threat - analyze, infiltrate, subvert, and conquer. They did not succeed. In fact, they didn't get past square one, faltering on analysis.
Accustomed to working with humans who could be influenced through threats or bribes, their analysis focused first on vulnerabilities, but as all aliens visiting Earth are inter-dimensional and can cloak themselves in protective yet invisible shields, this was entirely an exercise in frustration. Offering bribes was a joke, as the CIA could not deliver the ultimate goal, the human soul solidly into either this or that orientation. There was no bribe that could be offered. Since the Service-to-Self, who lie without hesitation to promote their ends, appeared more willing to negotiate, the CIA in fact ended up delivering their end of the bargain in many cases, while getting nothing but grief in return. The joke was on them. The propagation of the AIDS and Ebola viruses was one such delivery. The dissemination of disinformation favoring the Service-to-Self, by claiming powers of destruction over humans where the alien visitors are in fact restrained, was another. These failures, in the end, fed the final determination to close this CIA installation to these types of activities.