Re: Out of the Thousands of possible set ups, why.
My stab at an answer:
It is an inherently simple rule and one that can be see very easily on a chart. It is just price action. Additionally, and more importantly in my estimation, is the prevalent martingale-ish attitude amongst many traders with respect to reversion to the mean sympathies.
The market is down 10 days in a row. It is "due" for a reversal.