It's almost ironic how these horror-levels of violence started. Even though extreme acts of violence have always been around in Mexico's drug world, it were indeed Los Zetas who were arguably the originators of committing these brutalities on such a scale as well as distributing these filmed acts to the public. Their original point of view was that if they would capture and slaughter a few rival cartel members in the most heinous way they could think of, it would scare all of the other cartels off and rivals would get discouraged from interfering with their routes. They actually thought that if they would brutalize only a comparatively few rivals to set an example their newfound reputation would do the rest and they would actually have to commit less violence in the long run. It's an age old guerrilla tactic.

As we can see, the opposite actually happened and as a reaction to the Zetas modus operandi basically EVERY active cartel in Mexico began with the dismembering, sledgehammering, beheading, flaying, burning, boiling, etc...and now it's just a continuous freakshow contest in trying to one-up and outgross each other when finding ways to butcher rivals.