Most shareholders don't think this way. The stock market is a purely impersonal game to them. There is no people behind the company, no morals, simply numbers that go up and down. Anything that affects those numbers to go down is bad, and anything that affect them to go up is good, no matter what the long-term goals or moral implications.
You can compare most stockholders to a purely instinctual creature, like a fly or a snake. An instinctual creature exists purely to breed and survive before it dies. That's it. It does not think on its own, and its behavior is completely predictable. Real humans, on the other hand, were designed to think, to exist beyond shitting, eating, breeding, and dying. A real human can think outside its own system of subconscious processes. It has memory and can think long-term.
While a single stockholder is a human-being, the collective of all stockholders is a predictable instinctual creature. This is also why a corporation is a predictable instinctual creature; stockholders have the CEOs by the balls, so they control all of the actions.
The only way you can ensure that a corporation will not turn into a unthinking collective is to: A) not get into the publically-traded market, B) enter the publically-traded market with unusual conditions (ie: Google), or C) do not give shareholders any sort of power to vote for new members of the corporation.
Rosalina: But you didn't.
Robert: But I DON'T.
Rosalina: You sure that's right?
Robert: I was going to HAVE told you they'd come?
Rosalina: No.
Robert: The subjunctive?
Rosalina: That's not the subjunctive.
Robert: I don't think the syntax has been invented yet.
Rosalina: It would have had to have had been.
Robert: Had to have...had...been? That can't be right.