Yes, it's a dark view of the American character.
My feeling is that the American psyche embodies both the best and the worst of human nature. There is a xenophobic strain that has permeated our culture since before we became a nation, perhaps stoked by our two-ocean isolation. Ironically, we are a nation of immigrants. One could imagine that this might inoculate us from the poison of racial and ethnic hatred. If anything, it has heightened the sense of isolation felt by some on the fringes.
The institution of slavery in a relatively modern society helped to solidify a mind-set wherein some human beings were considered, legally, less "human" than others. Glowing embers of that attitude continue to smolder beneath our national surface.
Economic hardship tends to bring such strains into stark relief and make them more acceptable, particularly when the have-nots or the aggrieved are seeking someone to blame for their current plight.
On the other hand, what makes America exceptional is that we have laws and systems in place designed to conquer those base and ugly forces of human nature that have consumed other peoples. It is our strength that we keep trying to better ourselves as a pluralistic nation, in spite of persistent setbacks. We are a nation of laws, thank God. Unfortunately, we are also a nation of human beings, with all our inherent flaws.