I have to bang out a 10 page analysis brief on this subject matter in relation to human rights abuses in a couple of days. I just watched this documentary as a warm up and it was really interesting.
These trans-criminal organizations, or "cartels" which is really more of a journalistic term, are ruthless. However, the state is under international obligations to its citizens while the cartels are not. Since the Mexican government launched its offensive in 2006, thousands of ordinary citizens have been murdered, disappeared or worse by both sides.
BBC: This World: Mexico's Drug War