Make sure you're distinguishing between the claim that P(intelligence = x|income = i) = P(intelligence = x|race = r,income = i), which would be that poverty screens off the effects of race, and the claim that P(intelligence = x|race = r) = P(intelligence = x), which is the claim that intelligence and race are unconditionally independent. The first claim is only relevant to nyan_sandwich's claim if by "good" you mean "better than income" rather than "worth knowing."

As it stands, both of those claims are pretty obviously false if you take a look an unbiased look at the data. Life is not fair.