How did the men find the glory of warfare that had been presented to them by the teacher kantork very different from the realities of combat?

Kantorek presented and idealistic, patriotic, and poetic rhetoric to teach his students the concepts of national loyalty and glory. He's called them the “Iron Youth,” in his letters. He implies they are hard, strong, and resilient, but he doesn't consider the horrors of the war, or the way the men will be trapped in a constant state of panic and despair.

Kantorek's speeches are cited throughout the novel, but as time goes by Paul and his friends become disgusted by their words. The boy's first hand experience has made them cynical about the importance and meaning of patriotism and nationalism. Kantorek had made battle seem glorified and death honorable; the men saw it as neither. They blamed their teacher for Joseph Behm’s death, claiming he failed to understand that no ideal, no matter how strongly held can offer protection in the middle of a battle.