One could also argue that the power of music is so strong that it can penetrate even the sad environment of angry young men, especially Afro-American.
This rap and hip hop music can uplift, as in a first step in trying to express anger followed by other expressions.
On a side note, have you also noticed that we have had music expressing certain aspects of the Afro-American culture for many, many years?
Blues expresses Afro-American sadness.
Jazz expresses Afro-American intellect and spirituality.
Soul and funk expresses Afro-American happiness.
Rap and Hip hop expresses Afro-American anger and libido.
Just pondering here.