Do you really believe it's the songs lyrics that gets them teared up?
Do you really not consider there may be an emotional link between them and the song?
Do you really not consider they may have suffered a loss for the country and this sparks their visible emotional expression?
Go ahead and laugh, hell, I'll mention something else that you can laugh at as well. Why? Because I, unlike some am not ashamed of it and don't give much a damn what others think about it.
There's a few songs (mainly Fleetwood Mac) that when played, cause me to get a bit teary. They were songs that were favorites of my mother. I couldn't tell you the lyrics as it's not the lyrics that get me, its the link between the song and my mother and memories that do.
For those who want to read the lyrics of the song some apparently choose to laugh at while they get teared up over ... here ya go
Born down in a dead man's town
The first kick I took was when I hit the ground
You end up like a dog that's been beat too much
'Til you spend half your life just covering up
[chorus:]
Born in the U.S.A.
Born in the U.S.A.
Born in the U.S.A.
Born in the U.S.A.
I got in a little hometown jam
And so they put a rifle in my hands
Sent me off to Vietnam
To go and kill the yellow man
[chorus]
Come back home to the refinery
Hiring man says "Son if it was up to me"
I go down to see the V.A. man
He said "Son don't you understand"
[chorus]
I had a buddy at Khe Sahn
Fighting off the Viet Cong
They're still there, he's all gone
He had a little girl in Saigon
I got a picture of him in her arms
Down in the shadow of the penitentiary
Out by the gas fires of the refinery
I'm ten years down the road
Nowhere to run, ain't got nowhere to go
I'm a long gone Daddy in the U.S.A.
Born in the U.S.A.
I'm a cool rocking Daddy in the U.S.A.
Born in the U.S.A.