I'm inclined to think that quite different feelings masquerade as "racism".
For instance, these three attitudes seem to have different causes and different symptoms:
(X = a person of obviously African origin, and Y = a person of obviously Anglo-Saxon origin.)
1. The hostility a low-status Y may feel towards any X.
2. The discomfort a middle-status Y may feel in the presence of a low-status X.
3. The hostility a low-status X may feel towards any Y.
A further aspect is the vocabulary of "racism": taboo words are available to a Y, that any X will find offensive; but as Anon has demonstrated above, no words of equivalent force are available to an X who wants to insult a Y.
This suggests to me that we're dealing with a number of quite different phenomena.
MrP