I found the next sentence of Vladimir's significant:

You quickly run into an authoritative and stonewalling attitude of the sort that you never get by posing similar questions to, say, physicists.

My model of human behavior includes examples of both the kind Vladimir described and your alternative explanation.

In particular I expect experts to behave as per Vladimir's explanation whenever they are weighing in on topics that are at the fringes of the their field. We can reliably find that experts overestimate the breadth and depth of their expertise. (Professional gamblers are a notable exception to this rule.)

In the case of economists it is not unusual to find an economist declaring that something will operate in accordance with one of those basic concepts and yet be unable to engage in exploring just whether the assumptions in the model are satisfied in the instance (at risk of discovering that their model is irrelevant). That would amount to surrendering intellectual territory on behalf of the tribe - something that few with the cunning necessary to become considered an authority would do unless absolutely forced.