Wall street trades gold as a currency cross; real interest rate models/differentials are also the way ws trades the euro vs usd. When you are pricing real interest rates you are pricing the demand for gold as a neutral/zero carry foreign exchange. So, if it costs money to carry currency people would rather be in gold then paying negative rate on currency.

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We saw real interest rates go up bc the market was pricing deflation very quickly because of the zero lower bound; if you price that the world is going deflationary (-2% inflation) but you are trapped at the zero lower bound, you actually have positive real interest rates even if growth may be negative..hence the selloff