A couple of coments:
First, agreeing with Seafox. Prior to the '60s, polite white people used the words Negro or colored for people of African lineage. Mean people used the "N" word, and, at that time, to say black or brown was considered rude. In the 60's, during the era of the civil rights movement in the US, fiery political activist Stokely Carmichael coined the term, "Black Power" in his book of the same name. That ushered in the era of "Black Pride." Then the terms Negro and colored became symbols of the past era when blacks accepted their status as 2nd class citizens in America. Even though colored or Negro were at one time considered the polite terms, they came to be seen as condescending, because, in fact, they usually were used that way.
It was around the same time(60's) that the phrase "Afro-American" started to come into use. That has over the years given way to the term "African-American," which, if I am correct, would be the most correct term currently. I think that black is still acceptable, but African-American is probably a little more correct, and, in a sense, more accurate, since there are a lot of dark-skinned Americans and immigrants who are Latino, Asian, Arab, etc.
2nd, I think that the US is a nation of one. This is especially true in areas such as the San Francisco Bay Area, where people of all races and ethnic backgrounds mix together socially, and in business, without a very significant amount of discrimination or hostility. I think that this is probably true to some extent now in all the big urban areas in the US, with the possible exception of some cities in the South. Years ago, growing up in Pennsylvania and living in Michigan later, racial predjudice was rampant in those areas. I don't think that it has disappeared entirley, but I do think that it is not considered to be very acceptable behavior there, as it once was.
But when I say a nation of one, I mean that black, white, or whatever, that when this country feels threatened, as it did after 9/11, the people here stand together as one. We all are proud to be Americans, even though we have a lot of differences, and even though some of us are not at all proud of some of the things that have happened in the past 5 years. Even though we disagree and have some bitter arguments, we will defend the other person's right to say what he wants, even though we totally disagree with him. The divisions in this country right now have more to do with approval or disapproval of the actions of the current administration than they have to do about race.
Does racism exist in America? Sure it does. It exists everywhere in the world, especially in Europe. In my experience, I have found Europeans, generally, to be much more racist than Americans. Just consider all the comments various BMs have said about things that are said to them or looks that they get when they are in public with their TGFs. I can't imagine that happening here. In America, we have really made tremendous strides in the direction of acceptance and tolerance between all races in the past 50 years. When there is conflict here, as I see it, it is more like members of a family fighting with each other. When the chips are down, and we are threatened by external forces, we come together as one! Plus, I really think that there are very, very few people here who actually hate anyone or would want to bring harm to anyone, because they are of a different race!