The way that you dismiss run selling is exactly the same way that people dismiss your argument. Some people are genuinely upset that other people get carried through top raids, because it's not fair and they don't deserve drops/titles from them.
Did you get locked out of buying a house because someone else bought one to resell?
I'm sure the reason that there's no official statement is because it's a Pandora's Box to take that step. Once they state that doing something in game for in game currency, that wasn't explicitly against the ToS, is now explicitly against the ToS, they end up with a flood of people reporting everything that they don't like. Run selling, early pulling, undercutting, selling off MB, casinos, PF discrimination, every stupid little thing that "isn't fair" is open game. Someone else's game experience is indirectly ruining my game experience, make it stop.
It's easier to deal with it quietly and hope it goes away with the new roach motels of Ishgard.