I wasn't looking for a "history lesson", or "artificial" characters. But if you're going to tell a story, it's a good idea to provide some context, and in the case of an historical movie, that would include some of the history relevant to the story. As for characters, you don't have to "invent" a character, or even give much in the way of details about who they are, to make them interesting and/or a character that you find yourself caring about or curious about.
As for the Luftwaffe, a combination of command decisions and delays, coupled with bad weather, were largely responsible for the time that allowed the BEF to get out of Dunkirk. My point is that, apart from a single line about armor, and nothing about what was going on with German command or the Luftwaffe, many people are left to wonder 1) how the BEF ended up encircled in Dunkirk, and 2) why they had so much time (around 11 days in all) to get out of there.
You're entitled to your opinion ("Zimmer is the second coming of Mozart!"), and I am entitled to mine ("Dunkirk" is hardly the greatest WWII movie ever made).
By the way, I am not trying to say that Zimmer never wrote a good movie score, or that he has no talent as a composer. But his scores for Interstellar and Dunkirk struck me as similarly ponderous and overbearing, and comprised primarily of very long, blaring chords played on strings and pipe organs. Again, that’s my opinion. YMMV.