Especially when margins are low, cutting some corners for a small drop in costs can lead to a large increase in profits. And when the damage done to society as a whole, the lives lost, the radiation released, and the animals drowned in your oil, are not on your balance sheet, they don't directly factor into the decision. Only the money they have to pay as a result does, and that's never enough to undo the damage, and often not even enough to scare other companies from cutting similar corners, because letting those companies really pay, would bankrupt it and costs jobs.
It's perverse incentives all over the place.
He made the company tons of money. I'm sure he would claim it "would never happen" to the new company as well. Yet he's not exactly leading up another energy company, is he?