Corporations in the US are structured in a way that many will act with ethics much lower than the median ethics of the employees.

The point isn't just that it would happen, it's that it would be rewarded and encouraged, and ethics preventing the most profitable action (murder) would lead to being outcompeted by an organization with a structure that allows its members to coordinate and profit from murder without their ethics preventing such action. i.e. the market will ruthlessly optimize ethics out of decision-making.