Going through AIT in the late 60’s I had black platoon sgt and a black senior drill instructor. Both treated me good. I ran into them a couple years later in Vietnam. They were truly nice people. I just do not recall racism during that era.
I was in the Army around the same time and had many black NCO’s. I remember this huge black E7 who was in charge of Transportation. He saw two guys struggling to get a truck tire into the back of a deuce an a half. He walked over picked up the tire (which by the way still had the rim) and tossed it in the back of the truck. I will guarantee you that dude never heard a racist comment directed toward him.