As I recall, it's more like a bit over 6000, for civilization as in "real cities." There are places like Jericho that may have been inhabited earlier than that but they weren't very big. The whole Neolithic Revolution from the earliest domestication of cereal grasses is generally placed in the last 10-12K years, so the find announced in this article seems to be pushing the envelope. I say "seems to" because it needs a better article.
Pick a date that is much older than that ...
Pick a date that is much younger than that ...
But pick a date, say right at 15000 years ...
There was no predisposition for the current consensus (whatever it is). It was arrived at by following a preponderance of evidence. It has changed over time as the evidence picture changed. Nineteenth-century writers on Egyptian Dynastic history used chronologies which yield older dates than those now given for things like the initial unification of Egypt, etc. This does not show creationist-style dogmatic inflexibility.
Do a google on "Civilization began 15,000" and you get a lot of hits. But it is still controversial, do a google on "Civilization began" and you get stuff all over the board including a lot of hits for 6000.
Of course, you already know what I think the first cities appearing 6000 years ago means.
They may have pushed the envelope a little, but it's not like there was noone else claiming 15,000 years ago to give them credence.
"This does not show creationist-style dogmatic inflexibility. "
No, but then since the scientific community doesn't have "the word of God", I wouldn't expect them to show complete inflexibility. Then again, this does show a tremendous amount of evolutionistic group think. That article presented no real evidence that the city was 15,000 years old. It's a date picked because of popular opinion, not hard evidence.
I dunno, I'm not getting into the creationist-evolutionist debate here, but just speaking strictly within a historical framework, I think there's a predisposition, in that there are a lot of a priori assumptions from the 18th-19th century that continue to underlie current theory. You mention Egyptology above, so to take that as an example, there is a problem with circular dating because Manetho's chronology is used to date finds in Palestine which are then used to support Manetho's chronology. To cite some other examples that are pet peeves of mine (i.e., this isn't directed at you, I'm just ranting, LOL!), the Bering Strait hypothesis has long been used as an assumption without any empirical justification; and C.J. Thomsen's Stone-Iron-Bronze Age progression was an a priori framework based more on Hegelian-era methodological assumptions than empirical data. I think there is a problem with some things like that which predispose the academic establishment towards certain hypotheses and against others. The problem IMO is that historians often mix methodological and empirical assumptions without realizing that they're doing so, so their intepretation of the empirical data is often premised on unsubstantiated and sometimes unconscious methodological assumptions.