we should demand an elucidation of the likely consequences of tax cuts and tax increases given our current situation. isn't exactly a rejection of your first paragraph there. It's basically a synonym for tangible implications for policy.

And dismissed as a rhetorical device doesn't mean it is useless, it just means that the concept itself isn't worth a whole lot in a policy discussion, at least not once you've got everyone in the discussion to agree that cutting taxes can be beneficial (which I hope is not usually something that requires much discussion).