I certainly don't have the detective skills that you and many other scam/spam busters have, but I had a hunch that there was something off with the way those two keep finding reasons to mention that particular wallet. It just doesn't seem natural. It looks like they managed to stay under the radar for quite some time because of the way they were doing it. They are not necrobumping threads or posting out of context like many spammers do. The threads they are posting in are about software wallets, suggestions and recommendations, places to buy and store coins, and things like that. At first glance, it seems like everything is ok, until you realize they are doing it regularly, but not too much to arouse suspicion.