It's not a prerequisite. There are people that can businesses ruthlessly and without moral regard for the choices they make. I think more often the morality of most businesses is misrepresented as absent for the convenience of those who want to evoke sympathy within the proletariat.

"Heavy weighs the head that wears the crown"; when you lead a large entity, there are always going to be people that are unhappy with your choices. I think by and large the great majority of businesspersons attempt to conduct business morally in general.