That's the point. Pretty much everything can fall into one of the 4 categories. No change is necessary for that to happen - all this at a time when folks are complaining that the site is full of mass produced stuff they could order themselves.
Stolen goods maybe? Though that may qualify as 'sourcing' with a broad enough interpretation.
I would expect a stolen wallet sold on Etsy to have been hand picked by an artisinal scoundrel.