While this is an excellent and sensitive overview of the history of computer science from a critical standpoint, it may miss the essential point.
This is that while the announced intention of Cold War data systems efforts was to indeed provide a logically closed structure that would ensure national security and a narrow form of economic growth (which excluded unions from power), as Edwards himself reveals, these systems in significant ways failed to accomplish their technical goals.
The problem is that people with the traditional liberal suspicion of computers miss either this fact or fail to grasp its significance. Edwards fails to grasp its significance.
What it means is that on the ground, in the apparently highly controlled mainframe computer rooms, a highly "open" and possibly even "green" for of chaos operated as software (in one noted example) bayed at the moon when it mistook the moon for a missile. This chaos was presented as its opposite in a rhetorical trick which conceals the labor, and in some cases the very existence, of software creation.
The troubling fact, invisible to humanists outside the field, is that the upper-level administrators of these systems did not really care that they did not work, as long as the public viewed them as a closed and working system. They'd also prefer to conceal the origins of the software that controls these systems in labor and in writing.
Edwards in the main fails to link this rhetorical sleight-of-hand to C. Wright Mills' work in which the general public is systematically deceived, and a white-collar class creates the tools of its own destruction.
The Sage air defense system did not work and did not, in fact, protect the United States from attack: what protected us from attack was the decision of men to back down from macho and nuclear-armed confrontation, including Eisenhower's decision to not back Britain, France and Israel in 1956's Suez crisis and Nikita Krushchev's decision to back down in 1962 over Cuba.
The real technical illusion is not that the closed world is "better than" the green world. It is to not fully close digital worlds but to present them as closed, and to prevent the rules of their closure from public oversight, and control.