W. B. Yeats, from Preface to The Oxford Book of Modern Verse (1936)
In 1936, as editor of a leading poetry anthology, Yeats made the controversial choice of excluding all of the World War I combatant poets, even though he had set himself the goal of including “all good poets who have lived or died from three years before the death of Tennyson  to the present moment.” The following is his explanation.
I have a distaste for certain poems written in the midst of the great war; they are in all the anthologies, but I have substituted Herbert Read’s End of a War written long after. The writers of these poems were invariably officers of exceptional courage and capacity, one a man constantly selected for dangerous work, all, I think, had the Military Cross; their letters are vivid and humorous, they were not without joy—for all skill is joyful—but felt bound, in the words of the best known, to plead the suffering of their men. In poems that had for a time considerable fame, written in the first person, they made that suffering their own. I have rejected these poems for the same reason that made Arnold withdraw his Empedocles on Etna from circulation; passive suffering is not a theme for poetry. In all the great tragedies, tragedy is a joy to the man who dies; in Greece the tragic chorus danced. When man has withdrawn into the quicksilver at the back of the mirror no great event becomes luminous in his mind; it is no longer possible to write The Persians, Agincourt, Chevy Chase: some blunderer has driven his car on to the wrong side of the road—that is all.
If the war is necessary, or necessary in our time and place, it is best to forget its suffering as we do the discomfort of fever, remembering our comfort at midnight when our temperature fell, or as we forget the worst moments of more painful disease. Florence Farr returning third class from Ireland found herself among Connaught Rangers just returned from the Boer War who described an incident over and over, and always with loud laughter: an unpopular sergeant struck by a shell turned round and round like a dancer wound in his own entrails. That too may be a right way of seeing war, if war is necessary; the way of the Cockney slums, of Patrick Street, of the Kilmainham Minut, of Johnny I hardly knew ye, of the medieval Dance of Death.