Serving in a war that ends in defeat does not mean what you and your comrades sacrificed was for nothing.
Afghanistan, Iraq, Vietnam — makes no difference.
Every action a person takes in this life matters. Every single thing any of us does literally builds the world those who come after will experience.
The news and politicians and historians play a sneaky little game with facts, highlighting the ones that are novel or advance their personal agenda while downplaying those they dislike.