It has everything to do with living in a PC world.
We are all hyper sensitive. We have been taught to be. Some words can never be said, even if they are being said when discussing them for what they mean to different people in different contexts. If I was a professor giving a class on race relations, and I actually used the "N Word," rather than said the "N Word," I might be accused of racism or fucking up in some way because I was trying to draw a distinction between how certain people use the word, for example. Even if I was the furthest thing on the planet from a racist.
Anderson heard the word "Jackie" and immediately assumed, as would most people, and as our PC world has conditioned us to, that Donaldson was calling him "Black Jackie" or making a reference to his race.
And maybe he was indeed. I don't know what was in Donaldson's head and heart.
But it's just as likely, and I think more likely, that Donaldson was calling him out for self aggrandizement, as a I said above.
That Anderson heard "racist comment" when the intent was arguably "you're a blowhard" doesn't convert it into racist.
Again, it might have been just that. But my guess is that Donaldson is too dumb to know that when he chose to go there, he would be opening the racist can of worms that he in fact opened.