There are some logical flaws with the sociopath label, but there is certainly some truth to it, at least from my own experience. I'll provide a single example.
One of my childhood bullies - let's call him Tom - is most definitely a sociopath, and he joined the marines, along with his two brothers who are not unlike him. All three of these guys have been violent for as long as I've known them. During middle school and high school (and the couple years after where he happened to live in the same city as my university), he would pick fights with anyone and everyone for the dumbest reasons. I think he did it just to do it. Oddly enough, despite all the bullying and "shittalk" towards me over the years, he never fought me - although we did come close a couple of times but I just laughed at his stupidity and that was that. One of the last "conversations" I had with Tom was shortly before he went off to boot camp (or whatever you want to call it) and I asked him why he was going; he explained that he had nothing else better to do so he might as well go kill some people. He said those exact words, and he was dead serious.
If you're wondering why I didn't avoid the guy like the plague, it's because he and I had a lot of the same friends and he would always throw parties as his house to which my friends would invite me. Despite Tom's overly violent behavior, he was always very popular with the ladies, and most people really liked him. This is the same guy who posts pictures of himself on facebook cutting off the heads of goats in his marine gear. My theory is that because of his aggressive behavior (and using it to "dominate" others), people perceived him as an alpha male. Can I get a second opinion on this? Because so many people liking such a violent sociopath has always bothered and confused me.
Back on topic though... while Tom and his brothers are an example of some confirmation of the article's statements, as far as marines (or army, navy, etc.) go, for every Tom I've known, I've also known at least a few very easy-going men. So the author is partially right but his argument is flawed. Violent sociopaths without education probably do gravitate towards the military and war, but the statistics have got to be way off - not nearly 80% - but that's just from the small sample set of my experiences.