I've just read one of the more compelling points I've seen in a long time. The following is an excerpt from an A Finer World response to some comments by David Brin. Emphasis mine, but not too different from the original:
Before I can tell you more about this disease, we should review some famous and recent psychological experiments which deal with how ordinary people deal with certain circumstances. In particular, I’m thinking of the work of Milgram and Zimbardo, as well as recent fMRI work by Sam Harris et al. (caution, pdf). Milgram conducted research into how people respond to authority. In his most famous experiment, under the guise of working as lab assistants studying the impact of pain on learning, subjects were led to deliver progressively greater electric shocks to another individual. Zimbardo conducted another experiment in authority. Individuals were assigned roles as either prisoners or guards. Once given such roles, they behaved in a manner most succinctly describable today as “like Abu Garaib.” Harris indicated that people find it very difficult to question statements they believe to be true, that different brain areas are involved in belief and disbelief, and that it takes less time to evaluate a statement we hold to be true than one we believe to be false.
If most ordinary people were exchanged with the guards who ‘just followed orders’ at Dachau, or Auschwitz, we know now that they would act in much the same way. Every-day evil is a product of environment, though that is not the same as saying that these people aren’t sick—they’ve simply been made sick by their environment. (Sick in the sense that we define mental illness in terms of behavior we find incompatible with accepted societal values.) From Harris, we may add that if they already believed in the authorities in question, in that case the German government, they cannot be counted upon to reliably evaluate whether that authority is just; they’re too invested in that system of belief. To evaluate that system would require a conscious effort on the part of those who were already a part of it.
It follows that the systems by which we arrange ourselves, the authorities we agree will govern our behavior, are critically important if we wish to see a change in results. If you take completely ordinary people and tell them that authority says you are legally and morally obligated to maximize profits to maximize shareholder value, that this is what everyone does, and that those who are opposed to this system are wicked and evil and it is for the greater good that sometimes this system has problems… it stands to reason ordinary people can do terrible things. Suppress information about the dangers of smoking. Enforce slave-like conditions. Pollute the environment. Produce products which break, requiring replacement. Deny healthcare. Arrange surveillance to break strikes. Have labor organizers harassed, and perhaps even killed.
Full article (which is generally worth reading) can be found here.