The human species is a creature like all others that is designed to evolve to survive in an environment, and this evolution is designed to fit with the speed at which the conditions within an environment change. Part of the ability to evolve and change is governed by intellect part by instinct and conscience. Instinct and conscience drives the male towards the most appropriate female and vice versa to achieve the best species adaptation for an environment. We as a species are adapted by instinct and conscience to live in groups , families and tribes, this, because the young of our species take a long period to mature and need protection and education. We as a species therefore have been successful by acting in groups and are vulnerable as individuals. The male of any species is designed by instinct and conscience to be attracted to and desire the females of their species although members of the human species may through intellectual thought and arguments like to deny this. The males of our species are by instinct and conscience as individuals and by group, programmed by evolution to seek and acquire females from wherever they are for the process of evolution via reproductive natural selection. On a reasoned intellectual level interpreting the male and female of the human species in this way and the males as the aggressor towards other males just to acquire their females is abhorrent to me as it should be to every other decent person but at the primitive and savage level which all species without our human material comforts live it is a a very common fact governing their existence.Profit had always been the only reason for war. The underlining justification to mobilize the willingness of the population may vary (religion, patriotism, or spreading the democracy and freedom, lol) The only reason we hadn't descended into a Global nuclear war yet... there is no profit in that. That doesn't mean it can't happen if some country decides that they have nothing left to loose or some group of people decides that there is no more profit to be made unless we start a new.
Profit, religion, patriotism are just in fact the excuses that our intellect uses to justify war and the killing of members of our species which accompanies it, the true reason is rooted in our conscience and instincts for survival through reproductive natural selection reasons that our particular “advanced” form of intellect find difficult and perhaps impossible to admit to.