I can't speak for anyone else, but as far as my hiring process, I don't interview like 5 candidates to decide which one I want for one position. I interview them one at a time, and if I think you are qualified enough to meet or beat my standards, then you get an offer. The strategy closely follows optimal solution for The Secretary Problem[0], and I passed the cutoff interview years ago. (I am very fortunate in this regard in that I've never really had headcount restrictions because every company I've ever worked for has basically told me "HIRE HIRE HIRE HIRE" and I can never actually hire enough people to fill that headcount.)

With that in mind, from my perspective the goal of diversity is to increase the number of diverse candidates in the pipeline, which should theoretically lead to an increase in diverse talent on the teams. The goal is NOT to reduce the number of white men in the pipeline. In other words, if you're a cis straight white guy and you're qualified, I'm not going to say "no, I don't need another white guy" and reject you just because of your race and gender. First and foremost, that's illegal. And second, it's a dick move. And I try really hard to live by Wheaton's Law[1]. I've never done that and don't intend to ever do that. Talent is talent, and any hiring manager would be an idiot to turn it away for arbitrary reasons. (Sadly, there are a lot of idiots out there.)

[0] https://en.wikipedia.org/wiki/Secretary_problem [1] http://www.wheatonslaw.com/