I took a class Sociology class in college called "Killing". Not a single time did we once ever talk about "authoritative" or "legitimate" killings of any sort. It turned out that this class was specifically meant for 'Criminal Justice' majors, people who were going on to be police officers and prosecutors. We didn't ever talk about war, the death penalty, genocide, eugenics, abortion, differential reproductive success, famine, none of it. The whole class was about homicide.
the worst part: those people will leave the class thinking they have the whole story.
the part you mention won't ever enter their mind-- it isn't under the heading of "killing" because "killing" only happens to the groups covered in class.
Back when I was an undergrad, I took one sociology class (on a different topic) and the faculty seemed especially sensitive about that sort of manipulation. I can't find a reference at the moment, but it had something to do with the CIA consulting with academics about their activities in South America in the 70s.
It was in 2010 at the University of Minnesota. I actually got a degree in sociology, so I know from experience that the rest of the department was much more critically engaged. In my other classes, we were doing postcolonial studies of globalization, studying race/class/gender and reading Paulo Friere, Marx, etc. It was all solid.
But this "Killing" class is where I discovered that the department was segregated into distinct "tracks". They had one for general sociological studies, and one for people who were going on to be police officers and lawyers: the "criminal justice" track. This "Killing" class was part of the criminal justice track.
Later on, I took a class in CSCL (cultural studies and comparitive literature) called "Aliens" and found myself wishing I'd discovered CSCL sooner.
I was disturbed and appalled.