There is always more to be said, but there are several answers in the FAQ that I think will help here.

This long comment from /u/elos_ discusses the role of previous Franco-German tensions as well as German militarism and expansionism in the war's origins.

This comment from /u/DuxBelisarius, although not directly discussing the war's origins, goes into a lot of detail about German war aims, and I think it ties in neatly with elos' comment.

These comments are not exhaustive, but I think they illustrate that the most salient causes of the Great War had nothing to do with nations intentionally participating in apocalyptic bloodshed for the sake of staving off revolution. I would also argue that, although war does sometimes increase patriotic feelings as people 'rally around the flag,' protracted war is probably more likely to bring about socialist revolutions than peace is. Large portions of the young male population go off, become skilled in the use of weapons, and develop feelings of solidarity with their comrades-in-arms. Meanwhile, on the home front, the material demands of war tend to make civilians tighten their belts a little bit. The fact that one of the Great War belligerents literally collapsed into socialist revolution during the war, and that others (Germany, for instance) experienced large socialist movements in the early 1920s, is testament to this.