Real life Asian American here. The Chinese are the main market for gold sellers. The money they receive from non-Chinese is just extra icing on the cake. Don't believe me? Go play a native Asian MMO and see how many people buy gold and sell gold. It's considered normal to do so. So guess what? To kill the gold sellers, you have to kill the gold buyers. To kill the gold buyers, you have to ban them. Hm....oh wait, I'm a racist for stating a fact. How dare I internalize racism against my fellow yellow squinty-eyed people. CURSE THE WHITE HETEROCIS PATRIARCHY WHICH CREATED THIS INTERNALIZATION.
But seriously, you won't fix this issue without blocking the Golden Horde.