The most plausible explanation is the guy failed the interview, felt bad about it, then wrote a version of it to make him look good and Google bad to punish them.
I find the thought more plausible that Google had 100s or 1000s of candidates and they weren't willing to interview all of them directly because most are usually crap, so they let some incompetent contractor do a pre-screening.
I really wish our industry could create some generally trusted benchmarks of skill that we could take once and then be done with. As things are, we have to prove basic programming skill with every employer. You'd think this wouldn't be necessary with more than a decade of experience and several degrees in computer science from eminent institutions, but apparently it is. I'm fine with employers asking very particular questions about the domain of work, but we shouldn't have to prove sanity all over again every time.
