In history we had thousands of wars; some over the stupidest things and some over realistic ideologies and resources or the eradication of a group of people thought inferior to the aggressors. It's all opinions but heres an example:
Some believe the United States went to Iraq to secure a Pro-American puppet government under the name and idea of "Democracy". Furthermore to secure the oil fields of Iraq to allow undisrupted flow gasoline into our tankers in this fine, super-capitalist (Had to add) country.
That hasn't really related to the question however look deeper and you'll understand. If the U.S Imperialism of Iraq was successful, would our country and Iraq be doing better or for worse?
Enough? So in a nice mannered argument over the morality of War - do you think War in its definition is correct? Human between human over a strip of fertile soil or gasoline and metals? Killing off a species of animals because they threaten towns or whether for religious or secular means kill off an population of human beings. We can bring this to new heights.
I believe War shouldn't be thought morally but from a broader 3rd perspective not that I ignore the gruesome atrocities and effects of it.
If an species of hostile animals wore in an region of iron metal and this to-be flourishing civilization had to kill them with wooden sticks to obtain the metal, it should be done. Does the animal species use this material? No therefore they should be emigrated to another area or be enslaved/killed off. Of course people are going to say its wrong a thousand years ago or during that time in another land because they weren't their to understand it. You have to make sacrifices even if the next thing suffers to survive. It's all about Survival and it makes as much sense as a starving child cannibalizing over another dead boy or eating something recently alive you thought was cute or it didn't have to be done.
If you saw somebody kill a Deer with a rifle, would you get upset? Probably because that was "mean", irresponsible but put yourself in that persons position. If you were hungry and had no money to purchase food and had the materials to make food out of a living thing, wouldn't you be holding that rifle and pointing it at a Deer licking your lips? Exactly.
Also War has brought Humanity boundless leaps into new places of science and understanding. I have faith in that if we didn't experience both World Wars, we would never be as advanced today. The theory of Radar would've taken longer would not if the U-Boat situation around Britain and Britain's desire to defend its island from Germany not be an reality. Think about rocket technology, without Adolf Hitler and the previous war things would be slower today. We can make up assumptions or in some peoples minds conclusions that we could've done faster or to late who knows, but history has documented the motivation of individuals in improving a certain thing or creating say the computer because X war threatened X country and X country brought television, cable and cars into the world thereafter. It is a deep stray away from the question but its still relevant.