I don't find it surprising at all if you consider what it takes to be an executive of a major corporation. A corporation, based on US law, is akin to a person (I disagree with this, but whatever...). A corporation's sole purpose in "life" is to create wealth for it's shareholders. Therefore, if a corporation was actually a human person, it would be one devoid of compassion, remorse or social empathy whose focus is only on money, i.e. a psychopath. In order to control a psychopath, one must also be a psychopath. And how easy it is to be a corporate psychopath when there are few if any legal punishments to correct your behavior.
This is why we have corporations responsible for polluting large amounts of public land, air and water. Responsible for poor product safety leaving tens of thousands of people dead in the name of profits (BP, GM, Pacific Gas and Electric, etc...)
Sure there are likely some unique cases, but I think that there is a disproportionate amount of psychopaths leading corps as compared to how many there are in general society.
Corporate executives are essentially the "brain" of a corporation. Corporations don't control themselves. In order to control a corporation, your main goal has to be profits. Maximizing profit is how you get to become a corporate executive. Even the most "moral" executives often cut corners on community benefits to maximize profits.