By reducing the suffering of those who partook in WWI to an adventure we insult all those who were destroyed by war.
Do you not enjoy any games/movies including non-fictional wars?
It would be disingenuous of me to say I've always felt this way. I was a Counterstrike junky in high school and I enjoyed a number of titles in the Battlefield series. So don't take my comment as a holier-than-thou indictment. But I have learned a different path and am trying to make a positive impact on this world.
If anything, I stand as a testament that that these games do not define us nor condemn us to being monsters. But I will discourage my own children from being entertained as they watch Hueys swing down over a Vietnamese village with Fortunate Son playing in the background as they bomb the shit out of a small village full of perfectly evil enemies. I did that, and I have learned that reducing the world to good and evil permeates every little interaction in our lives until it becomes exceeding difficult to live the Golden Rule of treating others as you'd like to be treated. Micro-aggressions against others dehumanizes us.
Lastly, you are correct, that imagined conflict is actually very valuable to teaching moral lessons, and there are plenty of ways to explore the idea of war with those who don't yet appreciate how destructive it is to reduce an actual conflict in our shared history to black-and-white terms.
I find this an interesting point of view. That said, there's also the point to be made that portraying wars as glorious adventures, we're definitely not helping to raise a generation of people who want peace.
Come to think of it, it may be that we're not showing enough violence when making media about war. I remember watching "Saving Private Ryan" as a kid. The opening scene of the Operation Overlord shook me very hard. Since then, when I think of war, in my mind I have a picture of young people dying horrible, painful and pointless deaths, crying out to their parents and God as they hold their own guts in their hands. I think this level of graphic presentation may be needed to really drive the point home.