That's his point. There is no conceivable way that even a large fraction of that debt is AAA. What instead appears to be happening is a vicious circle:
* The finance industry engineers new ways to massage riskier debt into AAA products
* The market eagerly devours all the new AAA debt, building new business models and expanding previous ones based on the increased availability of risk-free products, thus
* Sparking demand for more AAA debt.