WTF.......uhhh BLACK people???

Why do we consider people like Halle Berry, Beyonce, Rihanna, T.I., and about 90% of the African American community BLACK when most of them don't have black skin at all. I have seen really light skinned and brown skinned people yet why are they called black. There skin is not black, and why do we call people from India "brown". This doesnt make sense so please explain.