The declaration of Independence states:

We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.

Today, the United States is the least racist, multicultural nation in the world.  To be proud of our nation is not to ignore our failures, including most notably slavery and segregation. But the better angels of our nature overcame these faults through the abolition of slavery and the recognition of the evil of racism.