While this may be true, my irrelevant take on the matter is this: just as skiguy said it might be simply that no one at the time saw it as noteworthy. You correctly state that lack of evidence against isn't proof of nor is lack of evidence for disproof. History is often the best guess based on what we have… changes when (if) new info. sufaces. Hope this answers your question.
Of course, no can disprove XYZ was said because it may not have been recorded, much like we cannot prove that there are no Leprechauns because they may be very good at hiding and leaving no evidence. But an inability to prove that XYZ was not said cannot reasonably justify the Senate Historical Office or the JCCIC asserting that XYZ was said anymore than we can justify asserting that Leprechauns are historical facts. This is so obvious that I didn't think there was a need to respond to skiguy.
