It appears to me that the individual handling sales for Fiddleback is a third party which also sells the work of various other makers on their site.
It's not the same thing as some of the other dedicated sub-forums on this site where the sales promoted are only by and for that particular maker, whether conducted inside their sub-forum or on the Exchange. I believe this is where the issue lies.
Fiddleback could conduct sales here or in the Exchange and nobody would bat an eye. It's having a third party dealer handling the sales and their site being promoted that I believe is at the core of the issue, since they are receiving the benefit of steering members to their site without having a dealer membership here.
I'll leave the rest to
Spark
as I'm getting outside of my lane.
ETA:
As an example, one of the sub-forums where I'm active conducts their sales on the Exchange as well as within their sub-forum. They also, from time to time, farm out some of their knives to a dealer which is not a site supporter. That dealer is never linked to, nor specifically mentioned in their threads or the posts of the membership...and everyone knows the reason is because the dealer is not a site supporter. So nobody is treating this maker differently, even if things were conducted in a certain fashion without the knowledge of admin here.