Some Literary critics have agreed that chapter 5, romanticizes the social aspect of war and the military. Does the author do this? To what...

Chapter 5 is a quiet chapter.  It comes after the relenting trench warfare descriptions of chapter 4 and the gas attacks of chapter 6.  Even though it is a quiet chapter, there is killing; chapter 5 begins and ends with animal death imagery: killing lice at the beginning and the goose at the end.  Comparing men to dying animals is a leitmotif here--and I would not classify the chapter, as a whole, as Romantic because of this. 

The crux of the chapter comes in the men's conversations about the war.  Should the war end, an older soldier wishes to return to his pre-war civilian job as a peat-farmer, but most of the others, especially the younger soldiers, can't see themselves doing much of anything, other than war.  So connected are they to war that even in their dreams they do not picture themselves as individuals with a choice, let alone a hopeful future.  More, all the soldiers agree that the war will never end.  This, by definition, is not Romantic.  This mindset smacks of the Realism of Crane. 

There are few socially Romantic episodes in the chapter.  There's certainly no love loss between the soldiers and the high command.  Tjaden hates Himmeltoss.

At the end, I suppose, the relationship between Paul and Kat does approach Romanticism, but the author ends the chapter with it and moves on to the horrors of war in the next, so I don't see a conscious Romantic effort on Remarque's part to develop it.  Such passages are, I believe, Romantic red herrings:

We are brothers and press on to one another the choicest pieces.

"May I never forget you!"

We are being set up here, I think, to hope for a future for these soldiers when, in the end, there will be none.  We know that, at the end, all these soldiers will die.  Remarque does not afford Paul with a Romantically glorious death: he dies without description, on the day the armistice is signed.  Therefore, this Romantic interlude at the end of chapter 5, we know, is fleeting.

Other critics, as the one in Sparknotes below, agree that only the ending is Romantic:

Paul marvels at the flood of emotion that he experiences while roasting the stolen goose with Kat. He and Kat would never have known one another in peacetime, but the war has brought their lives together in a crucible of horror. Their shared suffering makes peacetime concerns and concepts of friendship pale by comparison. In many ways, the bond forged between soldiers in trench warfare is the only romanticized element of Remarque’s spectacularly unromantic novel.

Again, I see this interlude as possibly Romantic, but as a whole, I don't see the chapter thusly.