Some of you must have really been tweaked that Paizo used fluff and crunch in an ad for dragon.
I personally don't mind the term (makes me think of graham crackers and marshmallows. Mmmmm...) But you really have to admit that the terms are sort of loaded. I really don't think ranting about it is going to change the common vernacular any more than rants by computer enthusiasts that the term "hacker" has been appropriated to describe their more criminal counterparts.
As where the judgement of vapidness in non-rules content might have came from... well, not to be mean, but I think that some vestiges of the industry earned it. Elsewise, you wouldn't see comments like frankthedm's here.
I still remember when I first read "Book of Taverns" for the ennies. I was really impressed. It seemed to me that writing of that quality -- well written and inspiring -- was really not that common in RPGs, or d20. If more books were up to the standard of Book of Taverns, I don't think that the RPG audience would have been so eager to adopt a term that implied lack of value.
Further, many of us are fans of literature, and regularly pay 3-6 times what we do for a novel on RPG books. Though there certainly is a talent to writing non-mechanical text, it generally doesn't have to be playtested or double-checked against rules standards, like skill point totals, balance, etc.. There really is a lot less man-hours that go into a paragraph of text than there is a stat-block than there is a paragraph of text. This being the case, it is easy to see where the perception that publishers who deliver more flavor text than rules material are trying to "pad" there books came from.
Edit: Disclaimer - no, I am not anti-non-mechanical text. I am "anti-non-useful-non-mechanical text". I am reminded of a discussion on the MotP, in which I really didn't recognize that it had what I call "fluff". Everything in there is useful to me and gives me ideas, without droning on as if the author was a frustrated wannabe novelist. Similarly with the scarred lands specific text in R&R.
My grammar teacher in JHS once advised that essays should be like a girl's skirt: short enough to be interesting, but long enough to cover the subject. To me, bad flavor text or "fluff" violates this in the former direction.