The movie for me was an average.
First part of the movie did alright showing the effects of the First World War on returning veterans like Desmond's father played by Hugo Weaving. Violent fights in the house and outbursts were common. He realistically portrays the effects of war guilt where survivors question why they survived and their friends didn't. Similar experiences were felt by the baby boomer generation with returning combat veterans.
Second part of the movie involves the battle of Hacksaw Ridge. Realistic portrayal of battle but Mel Gibson ruined it with too many slow motion shots. Most of us who follow WW2 have seen real stuff from WW2 in Color / Apocalypse - The Second World War type documentaries, and therefore slow motion shots ruin what could have been a decent movie.
In the United States those who form the alt-right that got Trump in are now a powerful force in US politics and society and believe in the right to keep and bear arms. It is probable they cynically see this as a subtle attempt to convince the population into giving up their firearms given the leading role of the character as a Conscientious Objector against the use of firearms.
Past attempts by the Hollywood establishment to use incidents like the Sandy Hook school massacre to convince the population to give up their firearms as well as their almost complete anti-Trump sentiments have made going to the movies made by Hollywood less popular, despite what sources like Wikipedia might say otherwise.
Secondly the alt-right see WW2 in a different light given recent information coming out about the background of WW2 and how the world was manipulated into it by the Banking Oligarchy. How widespread is this knowledge and how it affects this movie viewership is unknown.