How did WWI become a moralistic war?

Change and continuity marked belligerent societies' norms and values during the First World War. Normative institutions such as marriage and the family proved basically resilient but "fatherlessness" propelled anxieties about unruly youth who asserted greater autonomy in terms of leisure and courtship. Non-marital relationships received pragmatic state recognition withheld before the war. Rhetoric of sacrifice and restraint, backed up by law, ordained norms for personal consumption, as seen in the regulation of alcohol and of sexuality, just as a coarse egalitarianism drove attacks on profiteering. The civilian-soldier distinction weakened with state-sanctioned repression of dissenters and anti-imperial revolts. Mass violence permeated societies and expanded the categories of expendable lives even if humanitarian mobilization salved some wounds.