Not arguing your underlying point, but the examples you chose are poor--all economists are well aware of the effects of a minimum wage, and of barriers to hiring/firing. It's people with no background in economics who don't understand those things.
I would agree if you said "most economists" instead of "all". On the minimum wage, a couple of Princeton economists wrote a scholarly paper pointing out how that didn't suppress hiring (sorry, don't have a handy reference) or increase unemployment. On barriers to hiring/firing, I grant that most economists would agree they are bad.
On the other hand, Krugman himself has been a strong advocate of nationalized health care. Milton Friedman argued how the health care problem is really one of licensing regulations designed to maximize pay for doctors. Imagine an American Software Association that decides how many licenses to grant every year, and you need those credentials to be a hacker. Yes, Friedman addressed the "quack" argument too.
