America is about freedom, first and foremost. Millions of people, the vast majority of them from Europe, came to this country to escape oppressive governments and to embrace new economic opportunities. Thanks to a system of limited government, they built the most prosperous and powerful nation on the planet. Anything that pokes a hole in this story is just a footnote.
America is exceptional, all right. It was born in slavery and the theft of property from Native Americans. The Founding Fathers were slave-owning hypocrites. The system was racist from the beginning and remains so today. American prosperity was built on slavery; American capitalism even today retains a whiff of the brutality of slavery. Anything that pokes a hole in this story is just a footnote.
America is an imperfectly realized ideal. Many of the Founding Fathers might have been racists and slaveholders, but the ideas and the system they created contained the germ of a better, fairer, more democratic tomorrow. The system has evolved over time, and will continue to improve with experience, a few hiccups along the way notwithstanding. America, for all its flaws, has been the final guarantor of peace and prosperity throughout the world. Today, it is more diamond than coal.
Pick one. Everyone else has.