Orthodox Judaism rests on chazal's interpretation of Torah. If they are shown to be wrong in the Chanuka story then they could equally be wrong with regards to Tefillin, Mezzuzos and the rest. Orthodox Judaism disintegrates.The answer: We accept that Chazal were wrong abut science. Why not history? If Chazal could be wrong about science without Judaism disapearing, why does the chance that they were also wrong about history spell danger? Anyway, in what sense were "Chazal" wrong about the oil miracle if "Chazal" were also the authors of the agadot which tell a different story? "Chazal" isn't a monolith. "Chazal" is made up of competing personalities and competing ideas. Their books contain stories which contradict one another. Some of "Chazal" clearly favored the oil miracle; just as clearly, others did not.
These sort of disagreements are essential to Judaism, and a source of strength, not weakness. Did Orthodox Judaism disintegrate when Tarfon and Akiva argued? When the Ramban called the Ibn Ezra a blind man? When Yochana bin Hurkanus was excommunicated over the protests of a bas kol? No. Diveristy and difference makes us strong, and Judaism is tougher than you seem to think.
Other correspondents are using words like "fabrication" or "nonsense" to describe the oil miracle. I object to that language. Even if there was no oil miracle, the story is still a valuable and useful story. It's still part of our culture. It deserves reverence. This is true even if the story can be shown to have evolved over time.
For more on this subject from an unlikely source, read this. It's a famous essay about baseball, and the creation myth that surrounds it which explains quite convincingly how tradition often makes for bad history. Much of what the author points out is relevant to out discussion. Examples:
Too few people are comfortable with evolutionary modes of explanation in any form. I do not know why we tend to think so fuzzily in this area, but one reason must reside in our social and psychic attraction to creation myths in preference to evolutionary stories- for creation myths, as noted before, identify heroes and sacred places, while evolutionary stories provide no palpable, particular thing as a symbol for reverence, worship, or patriotism. Still, we must remember- and an intellectual’s most persistent and nagging responsibility lies in making this simple point over and over again, however noxious and bothersome we render ourselves thereby- that truth and desire, fact and comfort, have no necessary, or even preferred, correlation (so rejoice when they do coincide).And who is the author? A man who knows much about evolution albeit a different kind of evolution: Mr. Stephen Jay Gould.