Diversity matters for a lot of reasons. Perhaps most importantly, demographic diversity is strongly correlated with diversity in points of view. You want the people building your products to come from many walks of life. Remember how Google+ had significant uptake in the rich white tech dude demographic? Not a coincidence. If you want the best people working at your company, you should want a group with similar demographics as the customer population, and if you disagree with that, you either believe there is something inherent about certain groups that makes them better or worse at these jobs, which is plainly bigoted, or you believe that there are external social biases which cause the discrepancies. If the latter is your belief, that's all the more reason to work to increase diversity as a corrective to those external social biases. Diversity also impacts the way that people see your company, which makes attracting a diverse pool of qualified candidates easier (few people want to be the only member of a certain demographic group) and is good for public relations.