It's called faith, to believe what you cannot see.
There is no proof that God does not exist, and there is no proof for the arguments made against him. Such as the Big Bang, and Evolution.
Whether war is bad depends on the reasons for fighting
In many cases war is nessessary and in no case is it ever pointless.
But, as long as people continue to act upon selfish desires, such as revenge, or otherwize (Radicals as an example) there will always need to be a need to defend against them in wars, battles, skirmishes, etc.
Plus, as long as the mexican border stays open, terrorists will get in.