I think you're missing the point of the "diversity movement". The point is that some classes, e.g. women and minorities face discrimination that's baked into the selection process, even when they eventual selectors are not showing a preference. You might try to hire based only on "merit, motivation, and results", but any measure of those things is going to be imperfect. If those measurements are themselves biased, then your selection will be biased, even if you didn't want it to be. The goal of diversity policies is, in part, to break through and counteract those biases.

Jon Stewart gave a post-retirement interview in which he talked about this issue in the comedy world. He initially wrote off criticism of the lack of diversity in the writer's room for The Daily Show, since he always told people that he was interested in hiring more women and minorities. He eventually realized that the channels along which people came to the job was already selecting for white males, and that more diverse hiring required rethinking those channels.

https://youtu.be/p1H7KxPlbQw?t=42m32s