Edit: typo
I think everyone knows that this is not a problem exclusive to Google.
From his perspective, I bet he's frustrated for the reasons he point out. If he never talks about it out loud, how would any one know? Keeping people silent about this issue is in the company's interest because they'll not have to really change, and they'll hire someone eventually.
I mean, I know I sometimes choke on problems I'm trying to solve in the privacy, quiet, and comfort of my own home on projects I really care about.
I don't know what went on in the interview but given what he said, I think I would be upset, too.
Too hard to say, tbh.
If you were a corporation trying to keep PR positive, would you hire someone that has shown themselves as an outspoken public mouthpiece and tip-toe around them to keep them happy, or just avoid the problem?
On the other hand, if it was a complex and reasoned decision that he's summarizing badly, then yeah, good call on their part.
Context is king here, and we have little.
And I'm pretty sure this is EXACTLY the type of guy you want to hire, I would strongly suspect writing mild mannered complaints about not getting hired on twitter has very little correlation with job success.
i.e. "You want to buy us because of this, and a decent part of this is on GitHub, running every day, but you'd rather not look at -that- code but -this- arbitrary homework assignment".