Sorry, but I'm going to have to disagree. Just because diverse races have ended up sharing a common land doesn't mean that they respect each other and/or get along. It just means that it's an issue that must be dealt with versus countries with less diversity. This is not the "final proof" as you say.
If we're really after the truth rather than warm fuzzies, let's look at some real facts taking Obama's election as a case study. If the U.S. is not racist, then why was there so much focus on Obama being our first black president? Why does it even matter what color he is? Why is it even mentioned, nevertheless celebrated and lauded as proof of how "far we've come." All the hubbub proves exactly how far we have NOT come that it's such a big deal. OK, that's a lot of opinion. Let's get down the facts I promised...
In exit polls from the last presidential general election, Obama won an overwhelming 96% of the black vote. He got 43% of the white vote and McCain got 55%. Oh yeh, we've come a really long way, huh? This is not about debating or disputing the results of the election. Staying on topic, I'm just pointing out the undeniable fact that there were many millions of people pulling levers based solely on color and nothing else. And then we pat ourselves on the back for how far we've come? We've got entities that provide college funding based on color, not on financial need. We've got so-called civil rights leaders that gain fame stirring up the hate between us with derisive speech. We've got millions of people calling each other brothers based on the color of their skin and heritage from centuries ago instead of calling each other brothers because we're all citizens of this same great country. We punctuate the color of our elected president instead of the man holding the office.
Sorry, but I think we're still a pretty racist nation. When we get to where color truly doesn't matter any more and we see men and women instead of whites, native Americans, blacks, Asians, etc., then we can truly say we are not a racist nation.