If Donaldson was sincerely comparing him to JR, one of the greatest Major League Baseball players of all time, it would have been fine. It’s because Donaldson was being snarky that there is an issue. So this is not racism, it’s within the normal range of trash talking.
If Biden started calling himself the new George Washington he’d get ridiculed 24/7. That’s absurdity for some practically no-name player I’ve never heard of referring himself to one of the most talented and significant players in the history of the game.
I am no south side fan but I can name several White Sox players. Anderson is not one of them.