A large part of the people that get killed in Mexico are not actually cartel members but bandits, criminals, thieves etc. that are employed by the cartels to sell drugs, extort, kidnap for ransom , street intelligence etc. or do their street work. The cartel members are much harder to kidnap because they are usually are armed as well as Rambo with grenades and all driving bullet proof trucks. So when rival cartel members meet each other there is usually a shootout in streets. But not all of the people getting killed are "employed" by the cartels, some have been dudes that just hanged around with bad people.