Half a League ≠ A Full League

Something that I noticed has been a major theme in many (if not all the books) has been the worth behind the war, or rather, the lack thereof. I think we saw this especially on page 24 of the Borden text. On that page the General is speaking all about how these men will die before they ever so much as get the chance to return home. Much like how all sides knew before Nov. 11, 1918, that the war would end, it seems as though the deaths of these men is worthless. That any aspect of this war up until this point in the texts we’ve read and so on has been worthless, and it was this worthlessness that reminded me of the Tennyson poem The Charge of the Light Brigade. I’ll include the first part of the poem below:

Half a league, half a league,
Half a league onward,
All in the valley of Death
   Rode the six hundred.
“Forward, the Light Brigade!
Charge for the guns!” he said.
Into the valley of Death
   Rode the six hundred.
“Forward, the Light Brigade!”
Was there a man dismayed?
Not though the soldier knew
   Someone had blundered.
   Theirs not to make reply,
   Theirs not to reason why,
   Theirs but to do and die.
   Into the valley of Death
   Rode the six hundred.
Cannon to right of them,
Cannon to left of them,
Cannon in front of them
   Volleyed and thundered;
Stormed at with shot and shell,
Boldly they rode and well,
Into the jaws of Death,
Into the mouth of hell
   Rode the six hundred.
In The Charge of the Light Brigade, the 600 know they are going to die (much like the men the General is speaking to), yet they go on into battle anyway. In daily life, if we know we can prevent an unfavorable result of something, we make ample effort to avoid that outcome. However, in both the text and the poem, the men being described know that they will die and that in the end their actions will be worthless if the war continues (as it often does because aren’t all wars a continuance of previously unresolved conflict?).
I wonder how these men kept their sanity and continually pushed forwards into dangerous and fatal situations knowing full well the outcomes. Was it drilled into these people that because they will die in favor of their country, their country will advance in the war?
Personally, I believe that half a league ≠ a full league and death counts do not measure the success of a war.