This is a usual by-product of affirmative action. Minorities having lower intelligence and skills get pushed along based on skin color and, having reached higher levels, start to think they're there because of their own competence. It's the old "I'm standing on third base so I obviously hit a triple" scenario. Odumbo is a perfect example.
I don’t know where you work, but race is irrelevant. All races have their idiots, and they suffer from the same flaws. Operational units are generally exempt from such individuals, but they are often diverted into management tracks where they then credit themselves for actual workers’ competence. As far as affirmative action, race is less a factor as you move into the executive level.
In many environments (specifically government, media, and academia), that level is constituted almost exclusively by the Peter Principle. Peters surround themselves with incompetent personnel, lest they be revealed as the idiots they are. The Kruger-Dunning Effect is multiplied across the board as the sycophants blow smoke up each others’ orifices.