Not to negate your points, John, but fundamentalists Christians in the U.S. chose the term for themselves, largely in the 1920's to start with. There was a movement to defend several "fundamental" doctrines from liberal, allegedly apostate, theology. At one time I could have given the full list, including original sin, virgin birth, and substitutionary atonement. In practice today, I think the one critical distinctive of avowed fundamentalists is the inerrancy and infallibility of the Bible; they say there can be no authentic Christianity apart from this position, which many of us find indefencible(sp.) for a myriad of reasons.