`  :: the sentence doesn't say that racism is about whites. It begins ``Critics argue that ...``, and is just saying that (according to those critics) the concept is applied ``differentially``, i.e. that some people focus more on racism on the part of whites than other racism. It's well enough cited.  my understanding is that the OP is referring to the phrase ``with a focus on such prejudices by whites``, quoted in the title to this section.   `