Because many African languages, like Zulu, lack many linguistic distinctions sufficient to produce abstract concepts regarding Time (Past/Present) and Rules (Obligation/Promise). So descendents of Africans and people who are closer in proximity to practical use of those languages are seen as lacking subtlety, lacking conceptual grace, less capable of exploratory thought and critical intellectual maneuvering — notwithstanding the Media Machine which primes expectations for cross-racial and cross-cultural interactions.
As a Black (and Native American, mind you) person myself, I constantly battle on a personal level with criticisms such as this, and through my own limitations with language. I am but one person. At the same time, I have read from the works of Samuel Beckett to the works of Wittgenstein to Galileo, Aquinas, Maimonides, Aristotle, versed in Spinoza's Ethics, trained with a B.A. in Philosophy. And I still find myself each day pitted against the installed social strictures present in all Blacks' lives; even with my Classical education, I often find myself barking up the wrong tree more often than not.
Each day I grapple with my tools, sometimes mystified by my own capacity to become conceptually paralyzed. And this becomes a circle of a vicious nature. Language itself becomes both a fortress blocking acceptance and a prison prohibiting liberation, as constantly, despite whatever linguistic finesse I might muster, it simply falls upon deaf ears.
We call this Structural Oppression. It does not disappear over night.
One important point MLK made during his campaign is that, and I paraphrase, equality will not exist until Blacks are able to fail at the same rate as Whites. I am quite sure the same goes for women; hence, why Miley Cyrus serves as a Debordian "Spectacle".
Georges Bataille says something I believe is relevant[0]:
A man who finds himself among others is irritated
because he does not know why he is not one of the others.
[0]:
http://theanarchistlibrary.org/library/georges-bataille-the-...