Calling people out is not being an a-hole. They are an a-hole doing this kind of arbitrage in the first place.
In general people sell dirt cheap to the community to help out locally, so when some hat goes and uses that... it is not "hey that's life" it deserves a spanking.
On a photo forum I am using in France, they caught a guy doing that. There was a lens on sale on a UK forum. The guy reposted the ad on the French forum, with the pics from the original poster, but with an inflated price. He had not even bought it, he just wanted to see if someone would buy for the inflated price!
The site rules state that situations like this should be handled in private and that the proper feedback should be left in the reefer ratings. Sorry but thread closed.