Because there aren't enough women applying. At my previous job, I interviewed 50+ people, and fewer than 10% were women. For the record, I advocated strongly for most of them, and contributed to several being hired, including one of the best engineers I've met. Companies have a hard time hiring enough software people in general, and there are many more men applying for software jobs than women. If there were some untapped pool of female engineers all looking for jobs, believe me, that pool would get tapped. It just doesn't exist.

> 95% or whatever the claimed pay gap is

According to wikipedia, "the average female's unadjusted annual salary has been cited as being 78% of the average male salary", so you can save a lot.

Because paying women less goes hand in hand with seeing them as not being comparable to male hires?