Vietnam didn't do that, old age did that. People, and especially men, get much more conservative as they get older. They get set in their ways and refuse to change. Not all of us, but the vast majority. What you're describing are typical middle-aged men, and older, and they would be that way whether or not Vietnam had ever happened. I see as many people like you describe who aren't vets, but near the same age. It's just coincidene that they're Vietnam veterans, and what the war really did was dump a large number of helicopter pilots into the workplace. There has always been animosity between the generations, going back thousands of years, and that won't change this week.