Suppose I have 1000 people from community and 10 out of them are gender minorities. I then have 5 projects, each with 10 members on board committee, and I want a representative of gender minority in each of them. And I choose hard workers based on merit, the best of the best.
In such case I will be choosing 9*5 = 45 people out of 1000, and specifically I add 1*5 = 5 people out of those 10.
So the board committees will have 45 members each with (worst case) 955/1000 = 95.5% percentile performance, and additionally 5 members of gender minorities, each with mediocre 5/10 = 50% performance.
The gender minorities will perform worse, because we specifically singled them out of the crowd. This is not how you improve diversity.