Many countries, including many in Europe have some very serious, heavy racial issues that are both more ingrained than those of the U.S and in quite a few cases more violent or openly discriminatory. The U.S. however is generally at or close to the center of global media familiarity and attention, so naturally, the theme of its own racial issues is disproportionately magnified.
How many major countries are overtly ethnically homogeneous in the world, willfully closed or hostile to anything even resembling the mass immigration from all corners that the U.S has welcomed for many decades with only moderate tension?
How many people in European states will openly speak of certain groups, like gypsies, muslims and so forth with extremely derogatory words, but barely be called out on it by anybody? I've seen it many times, and go back to my point above, that in the U.S. the same things would and do simply get more intense media attention.
The U.S absolutely does have a number of very serious racial conflicts simmering at all times, but all things considered, I'd say the country does a remarkably good job of usually keeping them from getting worse, regardless of its high tolerance for free speech of even the most offensive kind.