The argument here implies, of course, that monetary policy decisions actually bear on the state of the financial system and could at the margin even be decisive to prevent the crisis and allow the system to recover. A second argument leading to the same conclusion stems from risk asymmetries.
Perhaps paradoxically, this is necessary precisely in order to reach higher interest rates in the future in a durable way. If we were to tighten monetary policy too soon, the interest rate increases might turn out to be unsustainable, and we might end up being stuck back in the ultra-low interest rate situation for even longer time than otherwise.