Taratare,
No I am not looking for stiff upper lip - far from it.
But people under immense stress don't react like this - far from it!
Dramatic music does not play in the background
messages like "hope is a weapon" don't pop up.
It verges on cringworthy in it's American style of storytelling and using scenes as a vehicle to pass messages.
Most of all though it screams fake - I don't believe I'm in Dunkirk I just think I'm watching crap actors following a crap screenplay.