Do not kill. Business strategy aims solely at profits, but businesses reserve amicable relations and avoid dangerous hostilities with employees and other groups out of a strategic concern for long-term profits.
People create moral and legal rules for similar reasons like promoting human flourishing, but there are differences. Should it be scientifically proven? Philosophical ethics provides a set of concepts and Ethics and Economics Economics teaches that businesses should operate with only profit in mind.
Can one be moral without religion? How should we best live? Now imagine that you are alone on that rock. In a similar way, when we disapprove of something a person does we may call it immoral or unethical, or both.