You mean a supernatural claim requires supernatural evidence. Supernatural evidence is an oxymoron to you so what a stupid thing to request.They were playing a word game with me, I had said extraordinary evidence, and they were trying to confuse definitions I guess. I did mean extraordinary, not supernatural, but I'll address the 'Supernatural evidence' part anyway.
I would possibly accept 'supernatural evidence' if you could come up with some valid definition of just what the hell would constitute supernatural evidence. It would also have to meet the criteria of 'evidence'. Is this evidence falsifiable? Is it circumstantial? Is it anecdotal?
Contrary to Mormon belief, a feeling in your chest is not evidence that your belief is true (or specifically the book of Mormon).
On second thoughts, 'supernatural evidence' in a sense is self-defeating. For if some supernatural occurrence is detectable in the natural universe, that evidence would not be 'supernatural' but would instead be purely natural. As the definition of natural is 'that which exists in nature' If the evidence exists in the natural world, then the evidence is natural.