Although I understand Modern Hollywood's need to intergrate people of different races to show diversity and appeal in modern movies, pretending it was there in the 1940's is a slap in the face to those who had to fight for equality later.
The casting crew decided to show the sergeant in the troop-carrying aircraft as a ass- kicking African American, verbally lambasting his white grunts, as well as the lead character being Black as well.
In reality, segregation in the military in the 1940's meant no mixing.
There was an African American Paratrooper unit ( the 555), but acceptance of the Black soldier was not as common as JJ Abraham's would have us believe.
In order to be politically correct today, it's not nessesary to whitewash over the wrongs of the past so that future generations forget they were there.