Article Review: Why the Keynesian Chorus is Cackling Like Chicken Little

In his article, "Why the Keynesian Chorus is Cackling Like Chicken Little", David Stockman mocks Keynesian Economics; however, there is also a very serious undertone. He fears that if the Feds listen to their chorus, it will lead to an even more destructive collapse of the "economic bubble".  This inevitable collapse is due to the government "pumping free money into Wall Street for 80 years" (in an attempt to resurrect the economy during the 2008 recession-now). From what I understand, Keynesian Economists believe the pumping of free money is "too tight" and want interest rates to remain at zero (because of aggregate demand), while Stockman wants feds to raise rates.
I thought this article was pretty hard to understand. I spent a fair amount of time googling words and acronyms (probably longer than it took to read the actual article). I am a little confused about how the pumping of free money has created a bubble around Wall Street. David Stockman refers to gamblers on "full risk" and casinos (references I believe to stockholders). How does ZIRP enhance this behavior?
I think I understand the concept of aggregate demand. Keynesian Economists want zero interest rates in hopes that it will increase demand. When interest rates are low, firms can borrow money to increase factors of production (better long run). Also, when interest rates on deposits (in banks) are low, people will be less inlined to put money into saving; instead they will turn to spending on goods+services. However, Stockman says that aggregate demanding isn't effective. He says that if you look at the data/charts (given), "nominal borrowing+spending show no elevation in aggregate demand. "
Before I even started this article, I researched Kenyesian Economists. Basically, it was started by Maynard Keynes as a solution to the Great Depression. It is also referred to as 'modern economics'. However, Stockman throws out their principes of low rates and aggregate demand, which makes me wonder why have we kept this standard so long? Why has this been effective in the Great Depression but not now? What does Stockman propose as an alternative?