Just a small quibble - I think you're creating a bit of a strawman in economists. Coming from both an economics and marketing background, I would suggest most economists believe that companies should act in the interests of their shareholders.
Charity can be a form of marketing just as creating a culture where at times short term profits may be sacrificed for long term benefits is also very much in the best interests of shareholders. Thus, the beauty of this economic system is that while you can profit by pursuing profit for its own sake (which can mean being charitable), I do think taking a principled approach results in more sustained and greater long term profitability - as I suspect irrespective of the outcome, this will be a case study for years to come.
An additional thought: this could potentially be genius from a business strategy standpoint against Microsoft. I confess I've been weighing the possibility of switching to Bing for a variety of reasons but because of this I'm less likely to do so.
After the dust settles, if Google is able to change Chinese government policy on search that would be monumental. If they aren't and ultimately leave China, that puts the spotlight on other infotech firms particularly Microsoft which has far more to lose by leaving China. On the other hand, if Microsoft chooses to do nothing and stay, it reinforces in the minds of users internationally a key point of differentiation between Google and Microsoft.
I have to imagine they have also weighed the business calculus on this. Where they might lose in China for now, will enhance their reputation elsewhere - particularly given how they've come under increased criticism in a wide range of fields. This decision whether intentionally so or in keeping with their stated mission is highly symbolic.
Further, don't think this won't help them in China over the long run either. When a "glastnost" comes to China, as it did Russia, if they're clever about marketing, using Google could ultimately be a symbol of new found freedoms. The fact that the Chinese government has made it difficult for them to operate, given competitors an operational advantage and enabled hackers that attack them and other firms, must make it an easier risk to take.
Being the idealist I am, I want to believe, and I think there's a good probability that doing the right thing here, will mean greater profits now and in the future.
Charity can be a form of marketing just as creating a culture where at times short term profits may be sacrificed for long term benefits is also very much in the best interests of shareholders. Thus, the beauty of this economic system is that while you can profit by pursuing profit for its own sake (which can mean being charitable), I do think taking a principled approach results in more sustained and greater long term profitability - as I suspect irrespective of the outcome, this will be a case study for years to come.