A subtle but damaging factor in this is the dominance of economists at business schools. While there is no evidence that economists are personally less ethical than members of other disciplines, approaching the world through the dollar sign does make people more cynical. This fact has been documented by data from an oft-cited experiment to test the standard economics teaching that, when offered the possibility, people will take a "free ride" -- and that it is "rational" for them to do so.
Take a group of workers in which each person's contribution to a given task is indistinguishable from everyone else's, and rewards (say pay raises) are handed out equally. A rational person (so goes the economics reasoning) will work as little as he or she can. In 1981, sociologists Gerald Marwell and Ruth E. Ames put this theory to the test with an experiment in which 12 groups were given a chance to take a free ride. Members of 11 of the groups refrained. That wasn't the case with the 12th group. How did that group differ? Its members were graduate students in economics. Those students had been mistaken about most people's behavior. But they had learned their own lesson well. All too well.
When It Comes to Ethics, B-Schools Get an F