Some of these guys took considerable trauma to their graves. My Uncle was on a couple of Pacific Islands, including Okinawa. He didn't really like talking about it that much. Now that I've seen some real footage, I understand why.
Sarah and I were members of a church that was made up of vets. WWII, Korea, Vietnam. Navy, Army, and Marines.
None of them talked about their experiences, either, other than to say that they had indeed served.
The only one who really talked was an Air Force vet who served during the Berlin Air Lift. And he let you know he was a vet. Repeatedly. The others? Only on Memorial Day. They just didn't talk about it or even acknowledge it.
It was a difference between those who saw a lot of combat and those who didn't.