If you wanted a corporate philosophy and hired a consultant to help out you would have ended up with something a lot more styled and poised and balanced and wooley than the one that google came up with... don't be evil. I listened to a podcast recently that said that corporate strategy is ruining the world i.e. it stops grounded logical human decisions being made. 'Don't be evil,' sounds more like something a person would say than a company and it feels naive and almost childish as a corporate strategy. The smart business person would choose their path not on a general consensus about right and fair but on any path against any logic that was put forward that could be justified as the most profitable out of all of those available. If it always worked out like this then you could hardly argue with it, but then Google don't seem to be doing so bad.
What if the expedient corporate strategy route meant unimaginative confused employees, or partners that don't trust you, or inconsistencies with your offering, or worst of all customers that don't have any good reason to choose you or even have reasons not to. Then that path looks fraught with problems. Like so many other things Google was ahead of its time. The anti-brand had the brand strategy of the future... make human kindness your big idea. Google don't always get it right and they have had their fair share of criticism where the slogan gets played back to them with an accusing finger, but generally its easy to believe that they mean it. Its pre-installed into their hardware.