Do you think asking a war veteran to share some of their stories could come off as rude?,

I have to agree with others, in that like most other traumatic experiences, war is not something that they want to recount, but why not channel that enthusiasm into being able to make their lives better. Go to a VA hospital and volunteer.... get involved with associations that help vets. Do something positive and get to know who those vets have become today.

my grandpa and grand uncles were vets of WWII and never once heard them talk about the war but they always stood proud and at attention at the Memorial Day Parade

Most I know don’t want to talk about it. They don’t like re-living it. Understandable.

they rarely want to talk about it.

It depends on how you ask and what they're willing to share. I'll talk to you all day about all the dumb shit my buddies and I did when we had down time, but actual combat experiences, not so much.

My father was in Viet Nam and didn't want to think about it, no less talk about it. It was a mentally painful experience for him.

Do know of my great grandparents who were in the wars. Have read one of there stories.

Most of those I know don’t really like discussing it. My father, who’s generally pretty cheerful just says, "it was awful but necessary" and changes the subject.