In times of insecurity, it does not take much to make young men "believe in the cause" of their leaders. As we found on the threads about religion, the word "believe" has many shades, and must not be reduced to the meaning "conclude by sober analysis". Also, there are various forms of "coercion", the most efficient one being haranguing by propaganda and peer pressure. If we could ask young men in Taliban controlled areas anonymously and secretly, most would still claim to be voluntary fighters.

So did young men in WWI, on both sides. Few, if any, really understood what was going on. Those who came to curse their leaders often did so only because the promised quick victory did not occur, and the losses were larger than anticipated. Others, who were originally critical of their governments' causes, resolved to fight bravely to help their comrades.

As usually, only few people felt they had to change their minds when the war was over and new evidence was available.

Therefore, if we now mourn those who died young in WWI and other wars, we should not judge about their morality at all. Praising anyone as a hero requires an analysis of the individual person's motives and of the cause.

At a given point in time, the leaders of a country may only have the choice to send their soldiers to war or to surrender at unacceptable conditions. Often enough, however, they failed to prevent that situations when there was still time. Most governments, definitely including all protagonists of the WWs, play with their military power to gain influence on other countries, in other words to bully them, and thus consciously take the risk of "unprovoked" war. Praising soldiers' heroism amounts to supporting that power play and encouraging governments to continue it. Not my idea of modern politics.