Depends on what you mean by "maximize," since "shareholder value" is a matter of opinion. Some might make the case for short-term rises at all costs, while others take a longer view of "value." In between are a lot of experts and self-proclaimed experts.
If shareholders value not collaborating with Nazis, then not collaborating with Nazis generates shareholder value.
Shareholders as a group have no need to be less good than themselves individually.
In theory, there is nothing logically inconsistent about a CEO both advocating for a better society and protecting shareholder value. Indeed, the former can sometimes help achieve the latter. If your country becomes Venezuela, that's not going to do your stock price any favors.
In practice, it doesn't matter. For better or worse, it is basically impossible to definitely measure the effectiveness of a CEO. Board members use their best judgement and the limited data they have.
You can be ousted whether or not you maximize shareholder value, as no one knows if you did or not. CEOs work for a board and that board can fire them for, in practice, any reason they want to.
In turn those board members work for shareholders that can choose them for any reason they want.
> Isn't that competitive ruthlessness exactly what people like about our current system?
I wouldn't guess so, no. I would guess people more like the effect of said competitiveness, which is an efficient market with lower prices and more stability than the other systems that have been tried.
> Citation needed, I guess.
Basic reasoning? Corporations are tightly interwoven with society. Their customers and employees are all members of said society, for one thing. Burning society to the ground is not going to work out well for any corporation.
But that is how it works, right? If you don't maximize shareholder value you can be ousted, if you don't where others do you will lose in the marketplace and cease to exist. Isn't that competitive ruthlessness exactly what people like about our current system?
> Corporations exist in society, and are not above society's concerns. Businesses operate through human beings, who remain human even in their roles as CEOs. One would hope.
Citation needed, I guess. For mid-small size companies this might be the case, but evidence seems to point to the opposite of this for any organization large enough to be its own thing outside of the humans and subsystems that comprise its pieces.