You should read the CJR link. The "shared sense of identity and community" is being descendants of the victims of the slave trade and not the color of their skin.
That's a strange definition, because it excludes the majority of the world's dark skinned population. If only the descendants of slaves brought to the Americas can claim to be Black, then there are no Black people in Africa. Hell, even Barack Obama can't claim to be Black, since he is a child of immigrants, not slaves.
