But it's not the only qualification necessary for the job. The other is to effect change in the organization. By your logic, if a black person is better at understanding the problems black people face, perhaps a white person would be better at getting white people to change things in the company.
I actually think both of those are wrong. You can feel horror at the Rwandan genocide or the holocaust or other massive injustices without being African or Jewish. You don't just intellectually understand racism in the US - I hope - you also feel it has to change.
Again, I agree the perspectives of underrepresented minorities are crucial here. But that doesn't lead to "every single chief of diversity must be non-white."