I have a different take on racism, and that is that humans, at the core (ie. probably genetically) are uncomfortable with a lack of conformity - the greater the difference, the greater the discomfort.
I recall reading somewhere that this desire for conformity helped the human race cooperate
and therefore survive in caveman days.
The other trait was a desire for togetherness (ie. a need to be social)
For these reason, social groups form, and those groups attempt to impose their desire for conformity on others of their social group. This scales up from from the smallest of social groups to the largest (society)...though peoples interaction (re demanding conformity) at each level depends on their perception of their own power to influence others, and on what they believe others should conform, and how strongly they believe others should conform to.
When societies develop independently of each other, different ideologies/beliefs/habits/cultures cross paths...this produces that uncomfortable feeling again...and as previously mentioned, the larger the differences, the greater the discomfort.
When those societies that cause discomfort for one another (this is important - 'racism' is never one way traffic) have obvious physical racial differences, you now have a symbol (the physical differences)...and symbolism has always held power in humans...
... because symbols allows our brain to form connections between any symbol (object, action, or concept) and a set of beliefs (our brain quite forms quite literal connections by the way) - the important one to racism is the connection between an object (the physical difference between the races) and a concept/emotion (first and foremost - the discomfort that all differences are filtered through )
(It is for this reason that the Burkha can trigger such ugly reactions in people - the symbolism vs the degree of difference)
... these neural connections allow us to react faster to dangerous situations, and therefore allowed humans to survive better - but they are also the source of our skills, language, learning etc
...lacking a connection that can identify if some thing unknown is a danger to us or not - the unknown can trigger all sorts of emotions in us (fear, wariness, discomfort, hate etc).
The above is why racism exists in every race on this planet. Only the degree will differ.
It is also why finding commonalities is the key to overcoming racism (ie reduces fear of the unknown, finds common ground, builds a feeling of similar society and conformity, which reduces discomfort etc).
It's the main reason I think all countries should have a firm integration policy for mass immigration of specific ethnicities (if you follow the above all the way through - you'll understand that the problem inevitably created if you don't do something to circumvent human nature...but I believe it's not education, but finding common ground that is the most effective method of reducing racism and creating greater social cohesion - so a true integration policy is the best way of achieving this. That is not to say that academic/advertising education shouldn't be an important part of the program, but that it's not the most important part)