War: a Daily Life Matter

"You know- we've had to imagine the war here, and we have imagined that it was being fought by aging men like ourselves. We had forgotten that wars were fought by babies." (p. 106)
When the English colonel says this, he means it. He had been captured for a really long time know and has been disconnected from the outside world. As he says, wars are fought by youngsters, by people who tend to carry on longer and keep going regarding the situation while with older people it is not as easy to do this because of their fiscal uncapability or because of their mental understanding of the situation. However, this english men believes this because he is liveng a rather "soft " side of the war.
Yes, he may be a captive, yes he may have "not seen a woman or a child for four years or more." Yes, he was absolutley isolated from the rest of the world. Yes, there was no hope in escaping and recuperating a life worth living. But it is also true that, yes, he was a "fourtunate" man in the sense that he found himself in a camp where he was well fed, where there were games and ways to spend the time, he had developed some fisical strenghth, he had people to talk to, he had somewhat developed a peacefull relationship with his captors. So yes, he was suffering, but compared to the other war prisioners, his life was great.
Reading this book constantly reminds us how terrible wars are, how much a prisioner suffers, how much a family suffers, how much the whole country suffers, it reminds us that a war will only bring suffering. Even though he talks about the colonel and how his concentration camp wasnt that bad, Vonnegut also mentions all the other people who did suffer. Those captives who were inhumanly treated till death, those who ended up burned and exploited, those whose lives ended with the war and those whos lives were changed by the war. Those who were walking skeletons, those who were burned to ashes, those who dissappeared, he also mentions all those who suffered.
I wonder why humans are so cruel with one another, and Billy wonders about this to, he even asks the "Tralfamadorian" how it is they live in peace and they tell him to loose all hope since humans will never go away from wars. However, they also let him know that even they, the "peaceful" society as Billy sees them, is not peaceful all the time. That they themselves also go through wars and disasters.
So I wonder, what really are wars for? Why do they exist and what is their purpose, if nothing positive is really extracted from them.