Jake R. answered 06/02/19
Experienced English and Writing Tutor for K-12 through College, TESOL
General Davis was an anomaly and no where near the norm for black officers in the US military. The fact that Davis was the first black General Officer, and that it did not happen until 1940, is also a clue to the attitude toward African-Americans, even among the officer corps.
Power is the wrong word when speaking about the relationship between an officer and a lower rank person. The better term would be authority. It was rank that was to be respected, not necessarily the person wearing the uniform.
From the end of the Civil War to the end of World War One, the US Military was segregated fully. Add to that, African-American units were primarily commanded by a white officer cadre. Yes, there were black officers after the Civil War. They were, generally, company grade and lower field grade officers; These are lieutenants, captains, and majors. It was not until the run up to the Second World War that black Lt. Colonels and Colonels were seen on a greater scale.
General Davis was at the start of the move by the US Military to desegregate. President Truman set the ball rolling, and by Vietnam, American forces were integrated- by the book, if not in practice.
But consider this: If General Davis had visited, say, Alabama after World War II, by law he would not have been able to sit in a white section of a restaurant. He couldn't have shared a drink from a fountain with any white person. Not even a white soldier that may have served with, or in a lower rank than him.
Also, remember Lt. Col. Lemuel Penn, murdered with two other black officers in uniform in 1964. Pretty segregation-like.