Yes it was but it's over simplistic to leave it at that. In my opinion the one man most responsible for the war was the Emperor of Germany, Kaiser Wilhelm II. He went on a fishing trip for two weeks and was unreachable while the machines of war ground on and on.
If he had stayed in Berlin for even a few more days he might have been able to avoid a larger war with Russia and France. By the time he returned events were out of his hands and the shooting started.
His second chance to avoid a greater war, and possibly allow a German victory over France was the short sighted invasion of Belgium, which was the excuse the near sighted British were waiting for in order to test their navy against the German navy.
