It's easy to distance ourselves from things that didn't happen in our country or in our lifetimes, but the reality is that we're just as bloodthirsty as anyone else.
Anyway, as far as I know, although my country has committed its share of horrible massacres around the world, none of it has happened in my lifetime... I just hope it'll last.
[0] https://en.wikipedia.org/wiki/Video_of_U.S._Marines_urinatin...
[1] https://en.wikipedia.org/wiki/July_12,_2007_Baghdad_airstrik...
[2] https://en.wikipedia.org/wiki/Abu_Ghraib_torture_and_prisone...
[3] https://en.wikipedia.org/wiki/Guantanamo_Bay_detention_camp
(not all are Iraq, but you get the picture)
The modern military recognizes the need for PR. Abu Ghraib was mostly still pictures because it was mostly leaks--press was allowed nowhere near the place. Contrast this with videos of Hussein's statue being pulled down or the "Mission Accomplished" press conference
If you cherry-pick specific instances, sure, there was negative coverage of the Iraq War, but the big picture of Iraq War coverage versus Viet Nam War coverage is very different.
http://i.imgur.com/sYuPCWP.png
http://www.slate.com/articles/news_and_politics/foreigners/2...
There were peaceful times throughout history, and they were followed by very bloody times. e.g. If, say, bloodshed follows a sine wave, we should at least wait for a couple periods before any proclamation that we've reduced bloodshed.
I think this 'outlier excuse' works when talking about serial killers or even criminal gangs, but I'm talking about violence on a much bigger scale, a scale where cultural factors are always contributing.