How is Luigi Pirandello judging patriotism in "War"?

The story is a polemic that takes place among passengers on a train. The thin man and his large wife, who are upset over their son's impending assignment to the front, are chastised by the other passengers for  not being tough enough to handle the possibility of their son becoming a casualty. All the other passengers also have sons who have fought in the war. They offer all sorts of reasons to rationalize their resignation at the fate of their sons; one says that since he has two sons at the front his suffering is proportionally worse; another says that young men crave glory, and if they die, they die "inflamed and happy," and are better off for dying young and not knowing the hard side of life. Most of the story is given over to arguing who is suffering more, and how this suffering must be borne out of patriotism. The sense is that the more a parent suffers, the more patriotic they are.
This, of course, is a ridiculous argument, which is shown at the end of the story when the wife asks one of the passengers if his son really is dead. The man's reaction—he breaks down in a flood of tears—suggests first that his "patriotism" is a simple fiction to shield him from grief, and second that, whatever story he might tell himself to justify his son's death, nothing can ultimately relieve his pain. 

In "War," Pirandello suggests that patriotism cannot justify the pain that is a part of war.
The fat man who injects his opinion into the train passengers' discussion uses patriotism to justify his son's sacrifice.  The fat man tells the other passengers that it is natural that young men like his son "consider the love for their Country even greater" than parental love.  He argues that patriotic duty is what motivates young men to make the ultimate sacrifice because they die "inflamed and happy."  The man silences everyone when says that in his son's final message, the boy was "dying satisfied at having ended his life in the best way he could have wished."  With this, the other passengers believe that patriotism is its own good, and justifies war's sacrifices.
However, Pirandello views this justification as limited. When the man must reckon with how his son "is really dead," patriotism does not help ease his pain.  The man realizes "at last that his son was really dead- gone for ever- for ever."  As the previously proud man broke "into harrowing, heart-breaking, uncontrollable sobs," Pirandello concludes that patriotism does not shield us from war's hurt.  Pirandello judges patriotism as something people use to justify war.  However, as seen through the fat man, it is unable to alleviate the pain that war causes.