A couple salient points:
The "best interests of the company" need not, and often are not, simply maximizing quarterly profits, share price, etc. Indeed, sometimes these things are odds with one another.
Moreover, shareholder value includes but is not limited to return on investment. It is simply most convenient _from a managerial perspective_ to simplify diverse shareholder notions of value down to the most legible lowest common denominator.
This is utterly and completely false.
If you don't believe me, here's what Justice Alito (known for his conservative/libertarian bent on the court) had to say in the Hobby Lobby opinion: "Modern corporate law does not require for-profit corporations to pursue profit at the expense of everything else, and many do not.