Aside from the main point of the article, I found the glancing reference to the correlation between lead in the environment and the homocide rate interesting. Had never heard that theory before. Seems to be easily exploitable toward the anti side of course, whether that is the intension or not.
Probably true. But other countries have also had violent streaks in their histories. Whether the author meant to single us out or not, this phrase tends to mark us as more violent.