Hello. You have not shown which text this question refers to, which makes it difficult to answer it accurately and satisfactorily. However, I will try to help you in the best possible way.
To persuade the end of the glorification of war, an author of a speech, must show all the decadence it causes. The author must emphasize how war destroys, kills and causes fear, misery, despair and sadness. Nothing happy can be generated in a war, because even victory is achieved through death and destruction.