BY HOLDING COPPER HAND RODS (OR APPLYING VOLTAGE TO ANY PART OF THE BODY) WOULDN’T THE ZAPPER CAUSE ELECTROLYSIS WHICH IN ITSELF COULD CAUSE HARMFUL BY-PRODUCTS THAT DAMAGE CELLS?

The zapper uses low voltage and a pulsed current so that this is not much of a problem, as general research about body electricity shows. Higher voltages with direct current applications, though, would definitely be a problem as they can destroy red blood cells.