From things I have heard about US forces stationed in the UK during WW2,, the feeling amongst the civilian population was against the segregation of black servicemen.
The way I recall Dad telling it is that he was about the only White at the supply depot. He had just been given command of it, he was fresh out of OCS, still wet behind the ears, and he was trying to run the depot by the book. The men under his command were disorderly, unkempt, out of uniform, and undisciplined, so he was trying to whip them into shape. After a few days of this, his (Black) first sergeant approached him and asked just what the heck he was trying to do. "I'm trying to get these men to act like soldiers," Dad answered. "But they're not soldiers," the first sergeant told him, "They're mules. They were drafted and put in uniform, but they were never even given basic training. They were just shipped over here to carry ammunition around so that if this depot blows up the Army only loses
one soldier ... and that would be
you, Lieutenant." Dad's reply to this was: "Not under
my command. If they're going to die for their country, then by God they're going to die as soldiers and men; not mules." The story goes that he then created his own basic training program, taught them to march, shoot, Army regulations, and all the other things they would have learned at basic training.
I'm hoping to find some corrobaoration of those events, or at least that Marston Magna was indeed where they occurred.