When I was younger I used to have a theory I called environmentalism, which seemed to better explain people’s’ behavior towards one another than how ‘racism’ did. That is, people develop opinions about the world and others depending one what their environment is comprised of.
For example, if you’re a policeman, you might tend to think of the world in three terms: cops, perpetrators (perps), and civilians. If you meet someone who’s not a cop, you’re already more likely to put them one of two boxes.
When it comes to race, I always thought that no one intrinsically dislike another race. At best, one is indifferent and forms opinions based on the types of people one interacts with. If you’ve got only negative interactions of a race, then you’ll have negative opinions. However, people, races, sexes, all behave differently in different locations and circumstances. For example, whites in the US are different from whites in England. Whites in the North are different from Whites in the South. Same with blacks. Blacks in Chicago are different from Blacks in New York and Blacks in America are wholly different from Blacks in Africa. A man who interacts with Blacks in Chicago is liable to have a vastly different opinion of Blacks than a man who interacts with Blacks in Africa.
I believe that people start with neutral opinions of other people and other places and form them after repeated interactions. If one travels, it gives one a bit of perspective that different people can be even more varied in behavior and beliefs in different areas, even amongst a particular race or nationality.