Ratio of 15-20% civilian deaths is not "exceptionally low" by any means.
> Starting in the 1980s, it was often claimed that 90 percent of the victims of modern wars were civilians.
> The Vietnamese government has estimated the number of Vietnamese civilians killed in the Vietnam War at two million, and the number of NVA and Viet Cong killed at 1.1 million—estimates which approximate those of a number of other sources.[19] This would give a civilian-combatant fatality ratio of approximately 2:1, or 67%.
> During the First Chechen War, 4,000 separatist fighters and 40,000 civilians are estimated to have died, giving a civilian-combatant ratio of 10:1.
https://en.wikipedia.org/wiki/Civilian_casualty_ratio#Cheche...
After all the hell and atrocities done by US in Vietnam, I absolutely do not understand how there was no strong resent towards US anymore after the war to the point of actively seeking and eliminating US targets like terrorist/spies do.
It was a humbling realization for me, and I have great respect for Vietnamese people not only for this.
"Trump Revokes Obama-Era Rule on Disclosing Civilian Casualties From U.S. Airstrikes Outside War Zones"
https://www.nytimes.com/2019/03/06/us/politics/trump-civilia...
Usually it's measured in the ratio of civilian casualties to combatants, and as far as I remember, US is keeping this ratio exceptionally low in comparison to other conflicts.
That's the key point here: your criticism applies to any war at all. War is hell, everybody knows that. To be objective in your judgement about US though, you have to quantatively compare different conflicts to each other.