Attacks on civilians during wartime are seen as a great evil and a "crime against humanity." Yet such attacks have been fundamental to warfare for thousands of years. The reason is simple. Civilians are attacked because they are the economic underpinning of the armed forces. The earliest written records talk of "pillaging the enemy lands." The reasons for this dreadful practice was twofold. First, but destroying enemy farms and herds, the enemy warriors would, for a year or so, be too busy keeping themselves and their kin alive to bother you. The second reason is the pillaging would force the enemy army to fight, so that the issue could be decided once and for all (until the next war.) Besieging cities made it clear that everyone inside the city was supporting the defense. The idea that civilians should be "exempt" began with the end of the 30 Years War in 1648. That war was particularly horrendous in terms of pillaging and the destruction of urban populations. These agreements cut down on the pillaging for a while. Then along came Napoleon and "total war" and no one has managed to put the genie back in the bottle since. But many of the atrocities against civilians today are committed by armies that are biblical in their organization and methods. Armed young men and teenagers maraud across the landscape in Africa, the Balkans and parts of Asia. They take what they want from local civilians and in the process terrorize the civilians into not opposing them. Adult males are often killed out of hand, another ancient practice, to get rid of potential opposition before they can get armed and organized. Calling this sort of thing a "crime against humanity" may be accurate, but won't stop it. Religious leaders have always preached against war and the pain it inflicts on women and children. But as long as the reasons for war (a whole other subject) you will have many of these wars fought in what the participants consider practical ways.