I believe in peace, because war never solved anything - except for ending Slavery, Fascism, Nazism, and Communism.
While it makes for a nice bumper sticker slogan it's a bit more complex than that. I don't know if you are trying to present war as some virtuous activity that stamps out tyranny. Sometimes it does but just as often war brings tyranny to power. One war defeated the fascists in Italy but another brought them to power in Spain. Nazism came about because of a war and then it took the Communists playing the main role in defeating them. In the few real shooting wars between Communists and Democracies, Korea was a draw, Mao won in China, and we all know how Vietnam turned out. Communism finally collapsed under the weight of it's own internal economic contradictions, it's inability to provide a decent standard of living, and peoples desire for freedom, not a war. So you can see War is a mixed bag and is best to avoid. It's little more than state sponsored terrorism pure and simple.
This is for a long discussion and I am not going there - since nobody ever convinced anybody about anything in internet discussions. I grew up in east block and saw the peace we had there up and close. The 1984 like lockup of never ending life situation is quite unbearable, but it is not possible for Americans to understand.
Living in freedom and comfort, far from any harm and far from oppresive/aggresive neighbors, coffee house pacifists can call war all they want - it's just words, words and more words.