It is a black only organisation, concentrating on race, namely blacks. Sure a white person can join, but that point is moot when all they go on about is black this and black that on the rest of their website. It is insulting to claim otherwise just because they allow a white person to join.
It is not a black only organisation, you can be white and be a member. This is in direct contrast to the BNP which specifically prohibits non-whites from joining. This one fact is a significant difference between the two groups and shows why Griffin was clutching at straws when he tried to draw comparisons betwen the two.