edit: Because, they are insulated from the bad repercussions of their harmful policies. Eg. Trafigura polluting the shit out of Ivory coast and poisoning people there. The CEO doesnt live there, he drinks bottled water and lives somewhere else in a gated compound.
Making those destructive choices makes things better for them so they keep making them over and over. If a CEO made a conscientious choice then it would most likely be at the expense of short term profit, which would diminish the extent of his power, sort of self-selecting himself out of the decision making pool.
Makes me imagine some weird distopian future where all people with power and wealth are forced to take some anti-self-deciet drug to prevent crimes against humanity :P
But who would force them?
If they don't, there is so much demand for the stuff (burning it is so incredibly useful) that it'll all be burned.