The issue that seems to be at stake with eBay vs. Newmark is that a company seems to be prevented from leaving a significant amount of possible profit on the table in order to provide direct amorphous distributed good - in craigslist's case the common person not having to be subject to (graphical) psychological manipulation when viewing classified ads.
A contrasting example is of Bill Gates's modern philanthropy efforts. It's certainly great that he's using that Microsoft lucre to make the world a better place. But IMHO it would have made the world an even better place if Microsoft had relaxed their business practices and not put us all through hell in the 90s.
The first approach leaves wealth and self-determination at the edges, while the latter suffers from the standard problems of top-down redistribution.
Practically, the root of the problem in the craigslist case is that they incorporated as for-profit and simply had an informal goal to begin with. A single stakeholder then sold their share to a purely profit-interested entity, which used that minority share to push craigslist down their own desired path (in addition to siphoning trade secrets). It seems like the only thing craigslist could have done is to formalize their philosophy-of-value when eBay wished to buy the shares, or ideally prior.
[0] Which allows the charity to be quantified. Presumably a shareholder would have a fiduciary duty claim if the board decided to give away 100% of profits.
Even unprofitable companies give to charities. Uber, for example, does this.
If Benioff starts talking about the importance of privacy and can make an argument that it aligns well with the ethical standards of the company, then he's probably safe.
He doesn't have to always do the thing that's most profitable as long as he isn't straying outside of the guidelines that have been set for investors.