What you just posted is something that no one wants to remember, because it is easier to just parrot the line about "youth" and "hippies", etc.
Those of us who lived through the times remember how people, including the young, were baffled by the nation's leaders and the way we were not fighting the war, eventually, many naturally wanted nothing to do with the unexplained war with no seeming purpose or goal, or end, we wouldn't even bomb the enemy, it was just year, after year, after year of half war, bloody combat, but with no seeming goal or purpose except to maintain an equilibrium between maintaining constant combat, while also maintaining the enemy's ability to fight us.
Fighting the Vietnamese was to be fighting a first class enemy, it was a true and bloody war with horrible conditions, in time it came to seem that people were merely being cycled through their time in the endless war, for no apparent purpose, as though it had become a habit for the politicians, it became clear that whatever unseen purpose it was serving for the politicians, that they weren't interested in defeating the enemy and that they kept stopping before delivering the death blow.
Look at these polls, the young were the strongest supporters of the war, and clearly the older people were mystified by the way it was not being fought, for instance leaving the north alone, and their harbors, and fighting for ground and then abandoning it.
Look at the over 49 age group, the WWII fighting age group, look at how quickly they changed in their support for the war.