alt Hacker NewsIt does not ignore the word. It subverts it, and that's the point. It's the system equivalent of "death of the author", which states that omes a work is written, the authors intent loses relevance and the work must be examined on its own. The aurhors opinion or relationship to the work carries no more weight than any other persons.
That's not "true" in any demonstrable sense, but it can be a useful form of analysis. As it is with "purpose of a system"
I'd go further and say this is also the cybernetics equivalent of the religious teachings about humans, specifically the whole "judge by one's deeds, not by one's words" thing. So it's not like it's a novel idea.
Also worth remembering that most systems POSIWID is said about, and in fact ~all important systems affecting people, are not designed in the first place. Market forces, social, political, even organizational dynamics, are not designed top-down, they're emergent, and bottom-up wishes and intentions do not necessarily carry over to the system at large.