Its virtually impossible to tell the difference between a product I'm middle-manning that's interpreted by investigators as real, vs a product that's interpreted as fake.
With books, nobody really minds if conceptually a book sat unopened on a bookstore shelf with the general public touching and pawing it occasionally vs a book that sat pristine untouched and cleaner on my home bookshelf, although one is marketed as "new" and one as "used", but in practice it usually doesn't matter. Also see the weirdness with $10 "indian subcontinent only" textbooks that normally sell for $200 to sucker american students, nobody complains their book was "fake" with a 95% discount to keep them quiet.
On the other hand, do that same game with toothbrushes and in roll the complaints.
This may be a problem inherent to online shopping in the long term. A copy of "Numerical Recipes in C edition 3" is a fungible commodity. Apparently, as per the linked article, that is not the case with fad overpriced gloves and toothbrushes. Possibly that type of product is inherently unsuitable for online purchase.