diversity fatigue
n. A form of mental exhaustion brought on by the constant attention required to ensure a workforce or other group is racially or ethnically diverse.
Last May, the major networks presented prime-time lineups possessing a striking shortage of minority faces. The press pointed it out. Interest groups complained. Network executives promised to do better.

Eight months later, the question of television's racial and ethnic diversity in front of and behind the camera remains a hot-button issue, sure to be prominent during the latest round of network meetings with TV critics in Pasadena — beginning with NBC on Sunday — as it did the last edition of this semi-annual tribute to platitudes, long-winded questions and hosted cocktail parties. Still, even those experiencing what might be called "diversity fatigue" — which would be, in all likelihood, just about everyone associated with the debate — had better get used to the topic, since it isn't going to be resolved any time soon.
—Brian Lowry, “TV diversity results will be years in the evaluating,” Los Angeles Times, January 08, 2000
Diversity in journalism should help, but recently members of the American Society of Newspaper Editors confessed to diversity fatigue — exhaustion from trying to meet self-imposed minority hiring goals.
—“Watching our language,” The Boston Globe, April 11, 1998
1998 (earliest)
A group representing the nation's newspaper editors has proposed scaling back its 20-year-old goals for increasing diversity in newsrooms. . . . "There's a widespread sense of diversity fatigue, not only among editors of newspapers," said A. Stephen Montiel, one of the dissenters who is president of the Maynard Institute for Journalism Education and a former editor for The Associated Press.
—Felicity Barringer, “Editors Debate Realism vs. Retreat in Newsroom Diversity,” The New York Times, April 06, 1998
Note that a similar term — compassion fatigue — entered the language around 1968.