Response: Ergo it is divine Q.E.D.
This is a common and needless impasse. There’s nothing about the faith of Jesus Christ that requires any assertion to be made about an item that is popularly claimed to be a relic. One can be a fervent, Spirit filled believer without making any assertion at all about what we are calling the Shroud.
The dialogue, however, is illustrative of a tension between naturalism and spiritualism (the latter not in the sense of sorcery but in the sense of acceptance that spirit is a fundamental characteristic of existence as it is known to us)