You must research the Black power movement. It may have been some refernce to the color of our skin in a colloquial sense but it also referred to several different levels of awareness and social protest.
We were supposedly negroes which stemmed from the spanish version of the word for Black- as such the black Power movement choose Black to signify that we were something previous to what we were redefined as.
Black is equated to darkness- the night- not necessarily something scary or ominous but something unseen- unexposed by light (much like the X which represented the tribe of shabazz- a signifier of unknown origins). Black then became a signifier of a common people who shared a history and place of origin but for all contemporary intents and purposes that history was hidden or Black.
Furthermore previous to the Black power movement we were colored, or niggers, or negroes. As the oppressor was White Black nationalists chose terminology that would counter the presumption that whites were superior- in that Black is a paralel term.
We were not offered that paralel until we demanded it.
(this form is all jacked i wodner if this will work)
bottom line- we call ourselves Black for more reasons than the color of our skin. To disregard the history and culture behind just cuz you (not you nah- whoever) dont know it is not fair.