You get xenophobic racism when you never see outsiders, but you also get racism when you see a <i>bunch</i> of outsiders in the wrong kind of context. A lot of black writers historically reported experiencing better treatment in Europe than in America, during an era where America had millions of black people and Europe had barely any. Now that Europe has millions of black immigrants, they have race issues.<p>If your society systemically creates a vast underclass of impoverished, poorly educated people who are oppressed as such <i>because of their race</i>, people are going to have their racism confirmed by those very effects. Likewise, if your society is flooded by a vast number of impoverished, poorly educated immigrants, people are going to hate the immigrants. (Judging from America's experience, this seems to be a temporary problem in most cases.) In either situation, you create racism by having <i>more</i> people of a different race, so long as those people are poor, segregated, or different enough to piss people off.<p>American racism was not as much xenophobic, it was always based on the difficulties of integrating immigrants and on the ongoing, cyclical oppression of the black population. You had some xenophobia during wartime (<a href="http://img.moonbuggy.org/superman-says-you-can-slap-a-jap/" rel="nofollow">http://img.moonbuggy.org/superman-says-you-can-slap-a-jap/</a>) but we tend to forget how much we hate other people after the war's over.