With all due respect, that's Bullshit, and anyone who cares to look into the provenance of the modern concept of a corporation can see that.
A corporation is a mechanism by which people pool resources and distribute risk such that endeavors unachievable by any individual of that collective group. This privileged collective vehicle, however, was based on the principle that the existence of the corporation was providing a service or good to the benefit of the society enabling the incorporation.
As a sibling poster mentioned, the Reagan/Thatcher years ushered in "the death of Society" and the birth of the "shareholder value" meme.
A corporation does not exist without the societal framework in which it is implemented. If corporations don't take this into account moving forward, the system that put them in a position to do what they are doing may find itself under attack from without by legislators, and within by an increasingly marginalized millennial demographic.
Point being, you can't sit here and say that the only obligation executives have is to their shareholders when the entire arrangement that makes that possible is dependent on the goodwill of everyone else who isn't a shareholder.
I acknowledge my arguments may not convince a hard core "shareholder value" believer, but I'm willing to put my money in the long run on the state of corporatism in America sidling up to a line after which there isn't going to be much they have to lean on once people start realizing that shareholder/not shareholder is becoming the new social division point. Either we're all countrymen, or we're not. If corporate America pounds the "not" drum hard enough, I have no delusions enough people won't get together to bring the entire house of cards to the ground.