Must we keep totally mum? Can we at least say, "It ain't so, look it up."
How about if they say cavemen hunted dinosaurs? How about if they say we never landed on the moon? Perhaps they opine that homeopathic remedies work wonders for cancer.
You could probably let someone live in blissful ignorance for at least one day on this turkey business, but just make sure they aren't throwing out the Lunestra and trying to cure their insomnia with massive amounts of turkey every night.