Decrying "exceptionalist" as in "spoiled brat" is not the same as claiming someone or something is exceptional. Maybe it is, we don't know yet. Exceptionally bad smelling? Exceptionally expensive? So many dimensions exist.
So for a segment here, if only to be contrarian (we have that right), I would argue for other reasons, let's yak about in what ways "America" (so much to say) is indeed "exceptional" (which it is).
One thing that's easy to observe is: a lot of the people who came here were underdogs, fighting some establishment back home and ending up with the short end of the stick, as some say. They then had to risk everything to start over here in the New World. And once they got here, they wanted one thing: revenge.
A lot of new Americans came here with a chip on their shoulder.
OK, I'm being a little facetious, but America's shores do harbor a lot of ethnicities within which "getting back" at whomever, is high on the agenda.
Given how America is a mighty place, and its control rooms appear open to anyone able to pay to play, why not seize those amazing military assets and extract from those enemies back home the price they deserve to pay (something high, obviously)? I mean, it's an obvious agenda to pursue.
Examples come piling in: refugee Gulenists wanted by Turkish authorities; refugee Falun Gongists seeking revenge against Xi, Ukes who hate Russkies, Russkies who hate Ukes, back and forth like that a million times.
They each want to rule the world, or at least get Americans to rally around their cause. Obviously I skipped over more obvious examples. The list goes on and on.
I think in that sense America is indeed exceptional. A huge number of its citizens came here with axes to grind, scores to settle, plans to get even.
For many, it was a maybe simple story of succeeding at the personal level, in spite of all odds, and having news get back home that so-and-so was no small town idiot after all. These stories are often heartwarming. For others, the story is more civilizational, about "the people" (or "pueblo") more generally.
Critics who want to play counterpoint will insist we remember all the people already here, before the floodgates were opened to colonization, by the invention of mass ocean going vessels.
The Mayflower was no Carnival cruise ship, we know that, but it was at least a step in that direction. People indulging in "religious convictions" could finally afford to book passage, and not have to help with crewing the ship or memorizing constellations (considered a pagan fixation by many).
True, Turtle Island was already festooned with stellar cultures, spread out and not forced into interpersonal violence on the scale of say Napoleon's people. Europe was far more densely populated, had more lethal weaponry, and exploited horses. The "Indians" had a lot to learn.
Napoleon decided to sell much of America to those Washington, DC people (a revolutionary avantgard), because he needed his troops to stay in the fight for the long haul. He needed to pay their salaries.
The Louisiana Purchase helped keep his struggling Empire going against England's. Not so long before, the USA had fought the same foe. The USA kept expanding west, fighting over slavery as it did so, with the industrial revolution more on the side of the Quakers in the long run.
Nothing regarding America's exceptional nature, as a platform for diaspora nations to consolidate and pass on culture, is contradicted by its original network nations, going back to Inca, Mayan, and Aztec to name a few -- the people we tend to call "Hispanic" today, for lack of a more intelligent word.
My narrative is more designed to switch attention from "melting pot" shibboleths (which I also use) and point out how "preserving ethnicity" was never an "unAmerican" goal.
You're allowed to keep practicing those rituals and rites, whatever they may be, and public schooling is not about countermanding your family's values on that score, as long as you don't interfere with the rights of others to perform otherwise, ritualistically and/or costume-wise (cosmetics, jewelry... we don't all share the same tastes, all right? Welcome to Walmart).