Why are the Nazis just "the enemy" in Dunkirk?

Possibly to make it more of a suspense thriller, rather than a typical war film. (Thank you Napoleon Wilson for pointing me in a direction).

You save a lot of money on paper,” he jokes about his 76-page script, which is roughly half the length of his typical screenplays. “Dunkirk” relies on visual imagery, not conversation, to propel the story, which can be a gamble. The characters are blank slates who offer no details about the lovers they left back home, their senses of humor or their previous heroic deeds.

“My idea was that, instead of trying to explain through dialogue why we should care about them, we use the language of suspense — we use the language of the Hitchcock thriller — to create immediate empathy with the people on-screen by virtue of their physical situations,” he says.

One could argue that using certain words or certain words too often, would take away from/pull us away from the sheer suspense and terror the viewer experiences with the soldiers, because it reminds us of "time", -a specific time and although there are surely references to no doubt point to Dunkirk and World War II during the film, they are subtle and aren't the most important thing.

AP: What kind of fascination does time hold for you as a filmmaker? It’s a sometimes underrated element of the medium, isn’t it?

Nolan: It is and it’s a misunderstood element of the medium. Conventional film grammar has an unbelievably sophisticated approach to modulating an audience’s sense of time. The films I’ve made, I’ve tried to grab a hold of what in most films is a subtlety. It’s there but the audience isn’t particularly conscious of it. I’ve tried to take it and use it for the tool that it is because I think it’s a tool that’s unique to cinema. The idea that we can go to the same movie theater, look at the same screen for the same period of time, and we could be watching something that represents hours or we could be watching something that represents millennia, and we’re fine with that. Cinema has this amazing ability to change and manipulate people’s feelings about time while they’re watching a film.

One film review that I think Describes it well:

Dunkirk is overwhelming in an exceptional sort of way, a film that demands close study of everything seen and heard. It’s a series of functioning contradictions, walking a tightrope in a stomach-dropping exercise of assured craftsmanship. It’s a film both timeless and of-the-moment. Airy, yet packed to the brim. Fast, but reflective. It’s a white-knuckle fable that strips the politics and gore of war down to the most elemental and essential storytelling. This is a film of fear, hope, and survival. The technical acumen, fleet-footed pacing, traversing narratives, and insistence on precise artistry and design make Dunkirk unlike any other blockbuster on the market. And yet it learns and borrows from the great films, taking the time to maximize its photographic, editorial, and musical elements to stirring effect.