Coal miners, fire(persons?), nurses, elementary school teachers and many many other fields are nowhere near 50/50. There are clear differences in genders and what they want out of life. He didn't in any way say the there are no women that can be good at this job. He simply pointed out that it's possible it might not be 50/50. maybe it's 60/40 or 70/30 and if you just try to hit a certain number you might not always be getting the best candidate for the position.
As a whole, if the tech industry was forced to be 50/50 tomorrow, we'd have to fire like 80% of the workforce. There simply aren't enough women interested in the field and qualified to do it right now. If you want to work towards having more women in tech, you have to start much sooner, at say the elementary and junior high age. Promote STEM more to them at those ages and maybe in 20-30 years we can be closer to 50/50. But it isn't happening tomorrow just because people want to change hiring practices. I hope that my daughter is interested in it when she grows up, and I certainly don't want her to be discriminated against, but saying it might not be 50/50 because different genders enjoy different things isn't in fact discrimination.