But they ARE new! She doesn't know how many possible buyers tried the shoes on in the store. But my guess is that every single pair of shoes is probably tried on at some point.
Selling on ebay is a learn-as-you-go education and if the seller never had a buyer who complained about a scuff on the sole of new but tried on shoes, she may not think to mention it.
IMO, you might consider mentioning to the seller that it's important to some buyers to be made aware of a scuff here or there and she might want to include pictures of the soles in future listings for shoes.
But again, as I said in my last response, you have to own some responsibility here for not requesting pictures of the soles since it's clearly important to you to put the first marks on them.
IMO, ebay wouldn't decide this case as SNAD because the "S" stands for "significantly" and for shoes (even new ones) to have a scuff on the sole is not a significant issue.
If you care about the soles, perhaps a B&M store purchase would be more appropriate. (This isn't to be critical. Everyone has her own tolerance level but I think this is OTT.) Personally, I'd block someone who is that picky.