The crayon color black is a word used to describe a color of something. The notion of a red truck, a blue sky, etc. is self-explanatory. The use of black when it refers to people does not relate to a descriptive color, but rather the race of the individual/group. A Black man refers to a man from a specific race much like a German man or woman refers to someone from a particular country/nation.
I believe it is time to recognize and honor the difference between a descriptive adjective (a black book) and a noun (Black man). The Black church does not refer to a building that is black in color, but rather to the people (Blacks) who are its members.
It is important to note this pertains to White people as it has similarly pertained to Spanish men, German women, and people from other nations. Race matters. It is beyond time to recognize the difference between the use of a color to describe an object and the reference to a race/ethnicity of men and women.