"less than noble"?
Ironic you say that, the primary reason we entered the war was due to our crusader-minded conception that communism in Asia would lead to a domino affect that would lead to an even greater spread of communism in the rest of the region. We didn't do it for resources or capital. Some people did profiteer, but they weren't the drive behind our fervor to prolong the war for a decade. Fear and the vain attempt to keep face were our primary drives in this messy conflict.
We originally took over for the French when they couldn't deal with their own inability to stabilize their own colony. Because we saw it as an encroachment of communism upon what we perceived at first to be a quasi-democratic colony, we thought we were fighting for their liberty.
Of course, I'm not trying to justify our action - merely to explain it. Much of the reasons for our intervention has been lost over the decades and with more communication between all factions of the world. Your generation, I think, does not understand our fear of communism because they were not around for the Red Scare of the late 1950's and 60's, with the rise of McCarthy-era communist witch hunts. It was a very real fear that communists from Russia after WWII had infiltrated the American infrastructure and levels of government and were seeking to incite a Bolshevik revolution in the USA. Very paranoid time for everybody, but I feel we Americans took it a little to close to heart. At the time it really boiled down to the two superpowers of the world: the communist Soviet Union and the democratic United States of America. Both sides incredibly paranoid of infiltration from the other: made us both do some very stupid things we would all regret in the hereafter.
The kicker: back then we saw it as an intervention to keep the freedoms of southeast Asia from crumbling under a spreading illness. To them, it was a fight against imperialists - they were not aware of the differences between us and the French before us who fought to keep Vietnam under control. It was a fight for independence for them, whereas we were not at all concerned with annexing them whatsoever. We didn't really understand them or realize their perception of it for decades afterwards.
As with the above paragraph - how it is taught in the US varies due to how murky and gray-scaled everything was due to nobody really knowing what was going on with the either side. High amount of public dissent in America, most of whom grew up to later teach it in schools, so most of Vietnam is taught in a negative light.
It's taught, and in great detail. We are still telling ourselves that we were the antagonists, as I am sure that's how everyone else in the world was taught about it, but on our own soil I guess we try to better explain the chaos that emerges from intangible feelings such as contemporary paranoia.
