> They want a one size fits all process that produces results, if not optimally, at least consistently.

There's an additional perhaps even more important aspect contributing here: the sociality of language and shared values in technology as social communities.

IMO If it hadn't been agile it would have been something else; we build common understandings with the terminology we have available, in order for our activities to make sense.

It doesn't matter if the terminology is applied correctly, viz. adhering to the theory (although many escape this accusation by a tacking "hybrid" onto everything). What matters is practical applicability: when we use these terms we're more often understanding rather than misunderstanding each other.

So the terms are used in more abstract ways than intended. (E.g. agile as methodology in health bureaucracy is kinda weird.)