True enough, at any economic level a black kid is likely to be at a disadvantage against a white kid in a country with that kind of racism (such as the USA and teh UK).

But regardless of colour, a poor kid is likely to be at a disadvantage compared to a kid from a comnfortably off family.

It seems to me that, since there's a disproportionately high number of kids who are both poor and black, tackling it at that level makes sense.