The term 'black music' is used when someone is referring to 'urban' or 'street' music. To substitute the word 'street' for the word 'black' is degrading and suggests that the street is a black persons place.
Some people say the term means music that originated from African Americans but the definition doesn't fit because it doesn't encompass UK Garage, Grime, Dubstep etc. which are all thought of as Black Music styles. Similarly, Rock'n'Roll is not thought of as a Black Music style dispite its origins.
The MOBO (Music of Black Origin) Awards has now removed Jazz as a category because it is no longer seen as a Black Music style. This fact strengthens the argument that the term is not used to indicate the colour of the skin of the original musicians, but rather the class of the people involved in the scene.
Anyone who believes in racial equality should find the term Black Music offensive.