I do IT work at a state university. As you'd expect with government institutions, we are really big on the EEOC rules and such. However, we can't force people to apply and for IT stuff, you get mostly men. Last round, it was all men. I don't mean we chose to interview all men, I mean no women applied, or if they did apply, HR filtered them out (HR does a basic "resume vs qualifications" check). Our IT group (we are only one of many IT groups on campus, there are women in other groups) is all male, at present. We had a female webmaster, however her fiance got a job in New York, so they moved there and of course she quit.
What, precisely, are we supposed to do to be more diverse? There are just not many women who seem to have the skills and wish to apply. We can't go and force people to apply, nor can we (legally or practically) say we'll waive the requirements for the job if you are a woman.
You can't hire those that don't apply.
So in terms of all this fluff up over Silicon Valley and diversity, I'd say how does their workforce numbers compare to their applicants? If in general it is the same, meaning say 30% of applicants are female and 30% of employees are female, 9% of applicants are black and 8% of employees are black, well then there probably isn't any discrimination going on. The fact that the numbers do not reflect demographics doesn't mean any discrimination on their part if they are simply not getting the applicants.
Also with regards to race, I'm not seeing why the 55% white number is problematic. According to Wikipedia, 72% of the US is white. If you count being hispanic as not being white (remember hispanic is an ethnicity, not a race) then the number is 64%. So per overall breakdown of the population, white people would be underrepresented in Apple by a fair bit.
That is also something I think people forget: The US does not have an even balance of all groups. Male/female has about a 50/50 split, but racial/ethnic groups are not nearly so even. It is still a nation dominated by fair skinned people of European ancestry, aka "white". The amount varies by state, of course, but it is quite a consistent majority.