It's not a business or HR decision, it's a political decision. Of course business and politics are intertwined.

Re: your papers. I've looked at such research before. I've yet to see such a study that's as conclusive as it's made to sound. Last time:

https://news.ycombinator.com/item?id=15490501

Randomly picking the last paper you cite for example, we learn that Spanish companies with more women on the board have better financial performance. Seems like an open and shut case! But then buried deep in the paper, we also learn that the Spanish government has passed lots of sexually discriminatory laws that financially advantage companies that achieve arbitrary gender quotas, most notably, only companies with a certain level of female presence on boards can bid for public contracts.

The Spanish economy isn't the best. Big chunks of the Spanish economy is propped up by government spending originating in ECB quantitative easing and it's been that way for a while. If companies with male-only boards are being discriminated against in public procurement contracts, that by itself is sufficient to explain part of the difference.

That's a common problem with papers that argue more women on boards = more financial performance. Invariably they are studying countries that artificially tip the playing field towards such companies already, making it difficult to disentangle the different factors.

If it's a business decision to hire more females, then who are we to demand top tech companies expand their college search range?

Could it not be a business decision to minimize risk?

(I, for one, am in favor of getting rid of all diversity quotas. Companies should be allowed to hire 100% black LGBT disabled women as much as they should be allowed to hire majority males out of elite universities.)

If you want to bring more women into your firm because you think they have some biological or sociological advantages over men in some areas then that's fine, do so. But look at the majority of posts in this thread, they're all about reducing gender bias. These other posts don't make sense in the context of an employer whose payroll is already proportional to the pipeline.

You're saying the opposite, that increasing gender bias will provide you with some economic benefit. At least what you're saying is rational and consistent.

"Bias" measures deviance from a parameter. Without agreement on the population being measured and the parameter in question, the term--and quibbling over it--is meaningless. You are defining the population as something close to "people who possess the relevant skills," i.e. the pipeline. Others are using "people who possess the relevant skills but aren't in the pipeline" or "people who could possess the relevant skills if factors out of their control were accounted for". Others, still, disagree with how you're measuring "possess the relevant skills". This is all reasonable disagreement.