I’ve never heard that 95% assertion expressed anywhere. But I’ve sure heard the short answer as to why the shroud is fake.
Adam Lee in Recap: The Goodness of Godlessness at UND | Daylight Atheism | Big Think:
There were questions about why we should be good to each other if the laws of nature don’t differentiate between good and evil; about how I could excuse all the evil done in the world by atheists; and all the other standard evangelist tropes. One questioner demanded to know how I could account for the existence of the Shroud of Turin, asserting that 95% of the scientists who studied it had converted. I explained that the cloth was carbon-dated to the 14th century, the same time when the shroud was first mentioned in historical records, and that a medieval bishop wrote a letter to the pope saying that the shroud was a forgery and that the forger had confessed.