It's beneficial to create the atmosphere that "RMT is impossible to remove, they're just a fact of life in MMOs". That acceptance contributes to and shifts people towards accepting the notion that "RMT is okay". There are people who actually verbally attack others who complain about RMT adverts, sometimes making fun of them, saying that you should just blacklist them and move on. When there's a strong social stigma against anything RMT related, newbies and highly active players naturally resist RMT. So the kind of silence promoted by the notion that "RMT isn't affecting you" is beneficial to RMT vendors.
Making people who are not going to be customers anyway feel helpless and powerless against RMT thus has its benefits.
It is the same reason why social media marketing is so hot these days. It is the same reason why controlling mass media had always been one of the most important things for any government up to 20 years ago, and true even now for nations where the internet isn't as pervasive. And it is the same reason why governments around the world are secretly paying people to spread pro-government comments on social media websites.
