Arnold Kling links to David Colander writing: "Not only are economists as a group not humble enough, what lay people are presented as economist's policy recommendations are often the policy recommendations of the least humble economist. In summary, my argument is that lack of humility in conveying the limitations of their results is the most serious ethical problem facing economists; it played a much larger role in causing the recent financial crisis than did the type of payments highlighted by Inside Job. Thus, and any new code of ethics for economists should deal with that humility problem."
I strongly agree with this - it's very similar to some of the points made by Robert Johnson in my link below.
The problem, once again, is that we all have different culprits in mind when we read something like this. When I read this, I immediately think of the mostly libertarian economists who want to radically alter and re-engineer the society that has naturally emerged and evolved in the United States by dismantling the social democracy that we have.
I highly doubt this is who Arnold Kling is thinking of as he reads this passage.
In fact, the very people that seem completely lacking in humility to me probably seem like poster children of humility to him.
I'm not sure where this gets us... probably nowhere.