Are you seriously making the claim that adding details to your fantasy world is not world building because those details are part of IRL culture? And just to turn it into a “stupid Americans not realizing…” post?

This was my answer as well. How out of place the MC feels each time he returns ‘home’ (and how his views no longer fit with societal norms), how he gets jerked around by the military he’s fighting for, how he just never can fit in and returns to service…

I’ve seen that happen to a lot of people. I think the story does an excellent job of conveying those emotions to someone who would otherwise be unfamiliar with them.