Simple, simplistic, simple-minded

Simplicity is often good, but simple-minded free market economists bury their heads in a sand of simplistic cases because they can't reconcile the economic systems with their easy cases.

Krugman fails to call bullshit on his friends and colleagues quite as vehemently (shrilly?) as he does on politicians. That's understandable, though fortunately his commenters feel no such compunction to politesse.