If one correctly uses the term "witch hunt," it has two essential factors: persecution of unpopular behavior.
If you are not witch-hunting, your choice to not participate = complicity; i.e., a black-or-white (no racist pun intended) Us vs Them shtick.
Racism has two components: a common perception: most black people are racist. That is because all black people are human beings first, and black people second. Most human beings are xenophobic, racist, tribal...a product of selection for survival. In this framing, "racism" is a subcategory of "prejudice," which latter has significant survival value. To quote (paraphrasing) Rev. J. Jackson, he becomes more aware of circumstances if he notes a black youth or two walking toward him, than if he notes an older Japanese woman walking toward him: simple jungle/street smarts.
If there is any question about the vile "racist" (as aka "prejudicial" tendencies of (your fave race/group here)), simply consider the murder of a Hutu girl who looked Tutsi, a few decades ago in the Rwandan genocide.
Secondly, why black people in the United States "can't be racist": Iff "racism" is defined as exercise of oppressive group power, then most black people, like most people, are prejudiced, but not racist...unless they are part of an institutionalization of personal prejudice This distinction is necessary, as most people understand they or others are "racist = prejudiced," and to claim that black people can't be racist is a second degree framing beyond current common experience and understanding.
Thus, psychology shows wide-spread prejudice; sociology shows processes such as "institutional racism." The latter has as metric, "justice/reparation." This is two-fold: first, justice indicates restitution (and permitting no further institutional oppression); secondly, reparation or restitution is difficult to calculate. E.g., the more accurate estimates of slave contribution to American GDP are in the range of 1-5%; more radical, outside calculations range up to ridiculous % of 50%. If war on poverty trillions, affirmative action, etc. are counted in the balance, economic restitution may have already been made to the "black community." The even-deliberate conflation of some emotionally/mentally hurt black person having encountered a perceived nasty white person in the days post-Jim Crow, with need for economic reparation smacks of infantile leftist manipulation.
Thus deconstructing institutional racism may include limiting affirmative action admission to poor blacks, based on economic stress difficulties, and disallowing affirmative action for middle-class blacks (per the logic that institutional racism qua affirmative action for middle class blacks is oppressive to others of similar socio-economic circumstances). The "witch hunt" in such specific and clear cases is then not against the nasty prejudiced white, nor against the nasty middle class privilege of better public schooling, but against the middle class whites, yellows, and browns who experience institutional racism when their black peers are given more admissions points. A similar case is plausible in today's relatively unprejudiced youth culture, i.e., that poor whites, yellows, and browns ought be given equal treatment as poor blacks, in terms of affirmative admissions policies.
So, your question has Wittgensteinian language game problematics, insofar as "racism" is conflated with prejudice, and the assessment of institutional racism blithely and erroneously conflates middle class blacks with poor blacks when considering e.g. affirmative action admission-to-college policy.