Another thought I had about my 26.8.05 post (re: Hotel Rwanda, The Crucible) - partially in reaction to some of the ridiculous behaviour after hurricane Katrina:
I think this topic relates in some ways to Kohlberg's theory of moral development. It is rare for adults anywhere to reach the fifth or sixth stage at which moral behaviour is compelled by an interest in the wellbeing of others or a powerful inner conviction. I would even propose that a great many of them remain in the first two stages in which only punishment or reward of some kind determines behaviour. Thus, while most people will avoid heinous criminal activity while there is the threat of punishment and rejection by society, these "standards" will quickly change once the social/political atmosphere guarantees them punishment or reward for an almost opposite behaviour set. In other words, the people of Salem were more than eager to act in their own interests the moment it dawned on them that they could do so legally and even "spiritually". The Hutus in Rwanda were happy to start killing and looting as soon as such behaviour became the political norm. The same could be said for many of the survivors in New Orleans who apparently thought the hurricane exempted them from the law.
Even Kohlberg's more common "conventional" levels of moral development allow for any sort of behaviour that is condoned by others or the current laws. The majority of SS officers involved in perpetrating the Holocaust, for instance, were not, once the war was over, serial killing socio-paths. Clearly, they were only willing to commit abomination when they could get away with it and/or be rewarded for it.
The heroes that seem inevitably to emerge from every instance of genocide or monstrous societal evil, are clearly those very few who have achieved the third echelon of Kohlberg's stages - who will do what is right because they care for others more than themselves, or just because it is right.