Your numbers are off. If you’re removing black females from the pool as “ineligible”, you need to remove white/other females as well. Sure black males may be 6.3% coaches and population, but they’re also probably close to that 14% of just the male population also.
White males aren’t 70%, they’re 35%. Your math (applied equally across grievance groups) means half the teams won’t have a coach!
Forgot to add, the half-black guy should count as full black, not half. When have you ever seen a mulatto identify with his white half? You’d think that’d be all they do, to get their white privilege, but nope, always associate with their black side only.