It's quite the opposite -- only civilized societies can have the kind of logistics, range, military culture, ability to support the warrior class (or standing armies), and numbers to engage in organized warfare. Conflicts between small bands of foragers can hardly be even called war.
Not to mention mass murder which absolutely requires the kind of discipline, organization and leadership only a very cohesive and civilized society can provide. It just doesn't happen outside of civilization, no one has the means, or could benefit from it. Anything of the scale of holocaust is only possible in a highly industrialized country.
> So now poor kids with few options are recruited into the military. Problem solved.
Actually, poor kids seem to be enlisting at lower rates (relatively) to richer kids:
> Enlisted recruits in 2006 and 2007 came primarily from middle-class and upper-middle-class backgrounds. Low-income neighborhoods were underrepresented among enlisted troops, while middle-class and high-income neighborhoods were overrepresented.
This and much more on the topic: http://www.heritage.org/research/reports/2008/08/who-serves-...