As long as I've been there, Google has been about 1/2 engineer and 1/2 everyone else. That's very atypical for large technical organizations, where if you have 25% engineering you'd feel pretty lucky. This also means that sometimes there is a 'engineers and everyone else' sort of thing going on. This is reflected in the exit stories, as are the very real problems that face globally distributed engineering organizations.
I find myself wanting to make excuses for some of the complaints mentioned in the article, but it really comes down to not every company matching every engineer, and if you have a large engineering org, you'll have some people who don't fit the org (the short story writer), and some people treated lamentably or regrettably by thier co-workers or managers.
A side note: the hiring process is much better than when I started. I've been sitting on hiring committees for 4 years now, and it is much more efficient than when I interviewed. I was interviewing for an odd position though, so it was even more extreme in my case (for both good and bad). I interviewed with 13 people and was given an offer within a few weeks. but back then a typical interviewer would have 8+ interviews, now we almost never go over 6.
That said, hiring is a dark art. I don't pretend to have an answer for that.