I'm a fiduciary serving on a board of directors, so yes, it rings a bell. We talk about our duty of care, our duty of loyalty, our duty of good faith.
Now, I'm on the board of a non-profit, but I can tell you that even for for-profit corporations, fiduciary duties consists of those three duties. There is no duty of maximizing profits. There's not even a duty of maximizing share prices, which is probably what you're thinking about.
To quote the US Supreme Court: "While it is certainly true that a central objective of for-profit corporations is to make money, modern corporate law does not require for-profit corporations to pursue profit at the expense of everything else, and many do not do so. For-profit corporations, with ownership approval, support a wide variety of charitable causes, and it is not at all uncommon for such corporations to further humanitarian and other altruistic objectives. Many examples come readily to mind."[1]
Tesla needs to state their goal as "make the world more sustainable" so people becoming owners can do so with understanding of that goal. Shareholders need to back this goal. But fiduciary duty means they have to serve the interests of their principals, not that those interests are profit over all else.
Let's not play this game of "there is only one legitimate goal for a corporation". That's not true, de facto or de jure.
[1] http://caselaw.findlaw.com/us-supreme-court/13-354.html
