Yes, this is the most shameful period in the history of war, and the US.
Acting in the role of the anti communist world policeman.
Not only did they drop more bombs/tonnage on Cambodia, than those/that dropped throughout the entire length of WW11, but spent more young American lives, and for what?
Their tactics were fairly limited, and apart from the brutal direct frontal assault, [Grandiose delusion, we can spend more lives than you r soul;] but included the mousetrap, replete with dope smokers, heroin addicts and ghetto blasters, (good morning Vietnam) where, I believe, friend and drawn out foe alike, could be mowed down by aerial mini-gun fire.
Finally, and as their most stupid action, they clearly confused Buddhism with communism, and then in that belief, imposed a minority (allegedly Christian) dictatorship, bereft of voter or popular support.
Yes they would say, he's a proper bar steward, but he's our proper bar steward!
Lessons learned?
Hopefully occasionally?
Ensure there's quite massive local popular support, rather than try and suppress it with a might is right approach.
Had Local Buddhists been assisted with their own indigenous resistance against northern oppression/territorial aggression!
The Du Ma allies could have won the voluntary support of both Buddhist Laos and Cambodia?
Instead the Buddhist majority Veit Cong (Charlie) were completely alienated and all but forced to side with the still hated communist north.
Moreover, following the Tet offensive, the North had exhausted its means and their very modest war machine/local support!
A rapid response counter offensive at that time, may well have won the day and a completely different outcome.
The other lesson therefore, stay the course and finish what you have started!
The US's approach instead, (and par for the course) cut and run and leave the indigenous allies in the lurch, and left to carry the can of almost endless reprisals/wealth relocation/redistribution!
And tens of thousands of wasted lives, health and trillions in expended treasure; and for what!?
Never again!
Rhrosty.

Did the Vietnamese people win from the war?

http://www.aseanmp.org/?p=3055

Maybe it isn't only Uncle Sam who should be damned.

Nobody wins from a war, not in the long run. But that doesn't mean that some wars don't need to be fought, unfortunately.
Obviously Vietnam was not one of those, despite what the Americans claimed to believe.
Some wars are inevitable, like the Nazi's were, and IS appears to be, so far, and Ukraine may yet become, the precursors to war and the innate responses to those are written in our genes.
Until or unless we come up with a socio/political system that actually takes our genetic heritage into account and devises systems for circumventing the now destructive ones we are doomed to endlessly repeat history.
I've seen International Realpolitik likened to a schoolyard, with it's bullies and braggarts, it's gangs and primitive interplays, and I reckon it's a good one, with the USA being the meanest kid in the yard at the moment, that one with the glazed look and blood under his nails who scares the bleep out of all the little kids!
And Australian politicians act like that disgusting little coward who hangs around sucking up to him!