I agree it was more of a marketing phrase. The code of conduct is more likely something like "Only do evil if it makes good money and don't get caught."
Early on, a lot of Google engineers (peering in from the outside, through news and correspondence) seemed to take it to heart. And to be heartened by it. Individually, and in groups.
That it's now called "marketing", speaks to fundamental changes at Google.
Isn't the bigger question though, why not continue marketing?
At some point it begins to be obvious when marketing is full of it - I think they passed that point and had to accept what everyone already knew.