"The meltdown also revealed dangerous links in the financial system few had previously realized—that losses in the U.S. housing market could trigger losses in huge stock portfolios that had nothing to do with housing. It was utter chaos driven by pure fear. Nothing like it had ever been seen before. This wasn't supposed to happen!"

The author admits the link here. Then lists all sorts of erratic behavior in the stock market. And ultimately fails to connect how quants caused an unsustainable housing bubble.