I'd like to really draw attention to the "for themselves" part here. Yes, this is a public document, and of course it serves a PR purpose, but the function of setting the terms for internal discussion at Google is at least as important.
I think that since most people aren't Google employees, they tend to focus on the PR angle of this, but I don't even think that's the primary motivation.
I didn't see the actual email chain (raw wasn't published?), but at Google-size it's conceivable there wasn't company-wide exec awareness of the details.
That's how big organizations operate.