That is a bad faith argument because the physical appearance of the person whose skin binds the cover of a book has absolutely no relevance to the information in the book. In fact, it wasn’t even Arsene Houssaye who bound the book in skin-- it was the book’s first owner, Dr. Ludovic Bouland, who did that.
Can you tell me what the color of a dead stranger’s eyes whose skin was added to a book by a third party has to do with a nineteenth century French novelist’s views on the soul and life after death?
You can’t, because there is no relevance to be had. It’s a bad faith argument.