Morality
Morality is a set of expectations that people use to trust strangers. It is the definition of self, based on an ideal of goodness for the benefit of society.
This survival skill is a great tool in bringing people together. Great things can be accomplished when many minds use their creativity in the same direction. This belief allows someone to sacrifice themselves for the greater good, or defend those that are like minded.
However, Good and evil are fluid and easily manipulated. Morality will allow and encourage individuals to discriminate against others based on beliefs and perceived evil.
Look at the moral manipulation that has driven a divide in our country. Pitting people against each other by re-defining and manipulating what is morally superior to each group.
Defining evil and acts of exclusion, are therefor moral, yet acts of war.