Of course racism exists. Not only in the United States but everywhere in the world, whether it is noticeable or not. People could write theses about why this happens. I think it all boils down to collective and individual ignorance. It is likely that racism will always exist. It can be passive racism, passive-aggressive, or simply aggressive. Why? Well, the world isn't exactly running low on ignorant people; we're in mass production, baby.
Even if racism completely disappeared, however unlikely, discrimination will still happen. We(humans), always find a way to make ourselves believe that we're above it all, it is just simply what we do. While it doesn't happen in every single case, it happens in enough: Rich people look down on poor people because they don't have money, poor people look down on rich people because they believe they waste their money, the middle class looks down on both the rich and the poor, and the other two look down on the middle class. Plenty of straight people look down on [insert other sexualisms here] because "that's just not normal," [insert other sexualisms here] look down on a lot of the straight people because of their close mindedness. Knowledgeable people look down on the less educated because they deem them stupid, the less educated look down on the more knowledgeable because they deem them snooty and condescending.
I could go on and on, but I believe that should be enough to make a point. In reality, we're all idiots who hardly deserve to walk on a planet as beautiful as this; it's hard to see because of all we've accomplished, but I believe it's pretty true. All of this is almost unavoidable; our differences in opinion are what drive us. Our aspirations to prove that X is better than Y, is what makes humanity grow. The alternative would be a completely homogenous coexistence with no need to change anything. Unless we only direct those opinions correctly, we can't truly live in a progressive society.
We like to separate ourselves from others for whatever reason; form clubs with people with similar opinions to cast judgement on others. Even here on the Vine.
Tolerance can only get us so far. The only solution to problems like racism is that everybody goes above the situation. A good question would be, "How do you convince 7 billion people to have the same exact opinion about something?"
Some food for thought: Since the dawn of man someone has been trying to "conquer Earth," or at least "control territories." We're still doing that.