I think there are two problems. The first is that if you assume that women are a) not inherently less qualified to do tech jobs and b) given an equal opportunity, then it would be reasonable to expect that 50% of Googlers would be women. But obviously the data shows that the ratio is much lower, so one of those assumptions is incorrect.
If you believe that the first assumption is incorrect - that women are inherently less qualified - then sure I can see why you think this is not a problem. Maybe you think they have different brains or something. But society as a whole, and Google's hiring department in particular, don't believe that, and so the logical conclusion is that women are not given equal opportunity.
I hope that you can see why that is clearly a problem. It might not be the fault of Google's hiring process - it could be a bias in the education system, or the exclusionary "bro culture" in the tech industry, or something else in some other part of society. Whatever it is, there's some subconscious bias somewhere that is holding women back, and figuring out where that is coming from could unlock a lot of potential talent, as well as making the world a fairer place.
So that's the first problem. The second problem is: who the fuck, male or female, wants to live in a place that is a complete sausage-fest? It's gotten so bad that it doesn't just affect individual companies or university departments anymore - in the Bay Area the gender ratio of the entire city of "Man Jose" is all fucked up.