gold buying is not only okay, but even good. Yes.
That's exactly it.
RMT allows people who have a lot of free time - to play the game for free by farming some money in the game, while allowing other people to spend less time grinding and more time in RL. Everyone's happy. Except envious kids who somehow feel that gold buyers don't deserve the pretty stuff that they are buying for their gold.
Please, take a moment to reflect on the fact that practically no one here is hating on gold farmers. People who farm gold and sell it for dollars. That's fine in most of your books, but when it comes to buying gold - you scream it's cheating.
Why?
Because you guys are a bunch of lazy jelous kids who don't wanna farm gold, but at the same time don't wanna pay for it, and hate people who can.
RMT is not the problem. Botting is, account hacking is - but you would be lying if you say that those problems are connected to RMT and nothing else. It's like trying to link OP classes to RMT. They are separate issues that can be used for RMT, but are widely used for soemthing else.
On the other hand, your mindless red-eyed hate towards RMT participants is the problem, but luckily - it's your problem.