Agreed.
I made it a guiding principle in my FC to have no shadow of RMT over our FC. As a result we have actually kicked two players for run selling. They were confused by the action, but in our view not only is it exploiting other players (in a directly exploitative manner that goes beyond standard economic activity such as buying/selling items through the MB), but it's also a key driver in giving other players an incentive to buy gil.
With regard to kicking people out of my FC for this kind of thing, or any kind of cheating/RMT; all I can say is, I've done it before, and I surely will do it again if the need arises.
I should add that the reason we view run selling as exploitation of other players, is that our FC is based on respecting other players (FC member or not), being friendly and helping freely - just for the sake of helping. My FC leadership is unanimous in agreeing that selling runs (even selling quick queues to Ninja/Rogue when that was new) is not respecting other players, nor is it helping others for the sake of helping; it's taking advantage of another player for personal gain, when the help could be offered freely. It just does not fit the ethics or spirit of our FC.
I disagree, I am certain that there are plenty of players who do make their gil legitimately, however, there are players who buy runs, and they buy them because they can't (or do not want to) obtain their wins or gear any other way, it's the same reason they buy crafted gear and high tier materia (rather than spirit bonding it themself) - "aint nobody got time for that...stuff".
That's not to say that all transactions for crafted gear or materia are RMT related - clearly they are not. However consider that the RMT bots you can see are all wearing gear that was crafted/melded by someone. Sometimes it's their own craft-bots, but more often it's legitimate players who are 'unwittingly' selling items to RMT Bots. Combine that with the players who buy items with purchased gil, and you can see that actually a decent proportion of the gil in the pockets of high level crafters could be tainted - without out their knowledge or intent.
That doesn't mean that there is any ill intent from those crafters or spirit binders selling materia, they can't exactly govern who buys their gear, nor where the gil comes from. But simple logic and basic math quickly lead to the conclusion that a lot of the gil in circulation is comes through RMT, and is injected into the rest of the economy through the purchase of high ticket items and runs.