If a nine year old thinks that they are right, they will yell and scream as such and will tend to tune out what other kids have to say to the contrary.
In some sense this is human nature. Once we make an argument part of our core being, it's difficult to let something new in to challenge it. I've done this to some degree in the past - we all do. But we like to think that eventually, adults have this ability to let their guard down. It's called learning.
But I've never seen a bigger group of 9 year-olds than amongst academic economists.
I posted on Krugman's post, but since he may not approve it, I'll just state the obvious. He, Fullwiler, and Keen need to meet for a few days, have some beers, maybe watch "A Beautiful Mind" on Netflix to get in the mood. Then, have a nice deep discussion about each others' assumptions - actively listen to each other, instead of taking cheap pot-shots.
I teach part time but I'm a full time real world employee - we can't afford all this childish banter in the real world. And frankly, economics as a profession, its students, and the policy-makers that listen to economics deserve better. This same kind of behavior reared its head when I worked as an economist at the Volpe Center though - I really do think economists have stunted social skills.
I'm not saying economists can or should agree about everything, but Jesus Christ, monetary theory is a big important topic. Economists need to at least agree on the basic mechanics of the financial system. I teach 2 weeks of it in my macro course. Right now, I have to teach it two ways: the mainstream way, and then teach it the heterodox way. This is not my fault that I have to do this. This is the fault of the profession - and it's sheer laziness and childishness.