In the poem "Dulce et Decorum Est" by Wilfred Owen, the lines you mentioned evoke a stark contrast between the idealized perception of war and its brutal realities. When the poet refers to a "high zest to children" and being "ardent for some desperate glory," he highlights how youthful enthusiasm and romantic notions about war often seduce individuals into believing that fighting is noble and glorious.
However, the poem itself provides a graphic and harrowing depiction of the actual experience of soldiers on the front lines. Owen describes them as "bent double, like old beggars under sacks," illustrating their exhaustion and suffering. The imagery of gas attacks and the visceral portrayal of death serve to dismantle any romantic notions about the heroism associated with war.
Owen's use of the phrase "Dulce et decorum est pro patria mori" (it is sweet and fitting to die for one's country) also serves to critique the glorification of war. The poem ultimately conveys that the reality of war is filled with pain, horror, and suffering, which starkly contrasts with the misconceptions held by those who glorify it, particularly children who have yet to confront its true nature.
In summary, Owen's work implies that while society may romanticize war as a path to honor and glory, the actual experience is often characterized by trauma, suffering, and disillusionment. The distinction between the ideal and the reality of war is a central theme in Owen's poignant critique.