What's funny is that this seems to be a more common thought among the younger generations now, too: Go back to like, 1985, 95, and 05 with these attitudes and people would blanche. Because we used to all be American. We had that idea of a shared identity, a team flag we all sat under no matter how different.
But to young folks, "America" doesn't exist, it's just another pastiche, a pop culture artifact of times gone past like "Toyotathon" or the Coca Cola Polar Bears. All the stakeholders overseeing and governing america have told us from birth that "actually you know there's no such thing as "american", it's whatever you want it to be" in between chastising us for the myriad sins of people who look like us. At a certain point, you just realize you're a sucker if you still want to be a loyal, patriotic American. You're a food to sally forth, fight, and die for a regime where literally every single person from the secretary in the foyer of city hall to the deepest catacombs of Washington DC sees you as a problem to be solved, an eternal enemy to stamp out.