How in the world did the human race survive without zappers for millions of years.
the weak and unfortunate (because of entries of toxic substances or poisons (in water/food) or of infection of parasitic worms or of accidents or of a predator/enemy attack) became sick/hurt and died...
Not all humanoid species survived, not all humans races survived, not all constitutions (depending on your genes and your environments) survived, only the more resistant childs survived, and men and women had probably one new baby each year...
What if somebody has a weak immune system because of a damaged organ or of a high load of a toxic substance (which can be difficult to eliminate), or of a parasitic worms infection, do you really think that this person want to give up and die ? I guess that no. That's why the hygienist approach is not always the best.
(these contradictions are not intented to defend zappers, because zappers are poorly effective (or totally ineffective) to kill parasitic worms in a human body)
As you say : "paragangster" leader of the "zapsters"