And I suppose one could argue that war is often just a manifestation of a desire for sex or power/money as an intermediary to sex.
http://www.wikisummaries.org/Prometheus_Rising
It fucked my mind when I read it :) It's a bit far out sometimes though, but it's a cool read.
Edit: Otherwise I don't see what the goal does to make the butchery of your fellow man any more or less obscene than it inherently is.
In Prometheus Rising RAW mentions that the reason monks take a vow of chastity is because it instantly frees them from one of the major hamster-wheels of the human condition.
Of course, I'm not planning to become a monk :) But food for thought...
The legal definition of obscenity requires that a work is meant to be arousing and has patently offensive sexual conduct, in addition to having no redeeming artistic value.
Therefore, adding sex into something offensive makes it more obscene.