Rhetoric, the art of persuasion was quite important in politics. It still is, but nowadays people seem to get off more on antagonism, thinking it's more honest.
It's easy to put down persuasion, but if you don't know how to put things in a sellable form you may be a deeper thinker, or you may just be muddled.
The author is talking about showing people who don't know, how to design a community sewer system and to get their minds around ideas hitherto unguessed-at in their culture, like rise and run -- engineering concepts foreign to them.
But then talk of "exceptionalism" or uniqueness is out of place. If you want to say, here's a formula for building a decent society, fine, but the more you get into saying that this is our unique model that belongs to us, the less likely you are to win people over.
Too much talk of American exceptionalism looks like an attempt to convince oneself of something. If you really believe in the country and its values, you aren't so desperate to prove that we are unique.
With international conspirators and domestic degenerates cooperating at multiple levels to overreach America as an idea and as a polity, and reduce people again to early-modern acceptance of Leviathan and the uniquely credentialed empowerment of benevolent autocrats and the societal soundness of privilege, class, and perquisite, why would anyone be anxious about our chances of pulling through against a host of enemies armed not just with money and thermonuclear weapons, but with the black arts of conspiracy, treason, and cabal?