Why did the students join the army?

In Chapter One, we learn that Kantorek, a small, stern man, used to lecture his pupils at length about the benefits of volunteering for the war. The boys, not knowing what they were getting into, were fearful of being labeled cowards for not joining. The "poor and simple" people knew the war would be trouble, while the others were ecstatic to be part of it. One student, Joseph Behm, reluctantly joined and was almost immediately killed. The boys felt let down by Kantorek and his kind. They had relied on their elders to guide them wisely into maturity, but once they witnessed death, the boys realized that their own generation was more trustworthy. Nevertheless, the boys patriotically and courageously joined and fought for their country.