I think they could have done something different than the not based on fact battle exploits as what the squadron did was heroic enough. Given the time period that the most obvious example of racial discrimination came from working class Frenchmen was a weird choice. And the Mud Marines, to take from Flying Leathernecks being introduced earlier in the movie I don't think was really needed. Especially when dealing with peace time officers, Colored Ensign or not. And the rest of the squadron certainly weren't.
Its not a buy for the library but a watch if it shows up randomly on TV flick. Many times better than Red Tails