"Although a soldier by profession, I have never felt any sort of fondness for war, and I have never advocated it, except as a means of peace." Ulysses S. Grant
Cor-Ai
War is such an awful thing - for some.
He and his team have chosen this life – the life of a combat soldier, well maybe not Daniel. They go through the gate with peaceful intentions but if enemies are encountered, they will engage. If war they find they will fight.
And if they are successful they get to go back to the base, get to go back home, a relatively peaceful home.
So many others have no choice, war comes to them. It comes through the Stargate, from ship orbiting their world firing destruction from the skies. Jack thinks of the women and children who cannot escape, caught in the path of the armies bent on destroying the other and too of the men helpless to protect their families. It's not only on other planets.
Jack has chosen this life, it suites his personality. The Jaffa have not chosen this life, they were bred to it. However, he is sure it is much the same for most of the Jaffa. But even for them as well as with him there are despicable things that weigh heavy on their souls.