I shudder when I hear that phrase, "right thinking people". Right by whose standards? Your's? Mine? bin Laden's?
Anyone can claim anything to be a "scientific fact" whenever they wish. But the true test of science is when those "facts" are corroborated by other scientists and found to be accurate. Over and over again. And even then, a true scientist will rarely come out and say that something is the absolute truth. At best, we can only say that there is currently no evidence to refute the data (or confirm them).