We've seen a similar phenomenon in some of the red states in the ideology conflict here in the US. There are people eager to kill someone just to have the experience, and who volunteer to hunt targeted groups (trans folk, lately) or as participants in an execution by firing squad. I remember in the John Oliver's first segment on the death penalty (he did a second one recently) executions were stalled due to difficulties obtaining the drugs used in lethal injections, and firing squads were brought up. The expert pointed out the difficulty finding one executioner, let alone seven. The officials suggested recruiting volunteers from the gun-enthusiast citizenry, which the expert saw as naïve.

I can't speak to firing-squad executions during the German Reich and the early stages of the holocaust, but I can speak to the Einsatzgruppen who were tasked with evacuating villages (to mass graves) who harbored Jews, harbored enemies of Germany or otherwise were deemed unworthy of life. The mass executions were hard on the troopers, and as a result Heydrich contended with high turnover rates.

This figured largely into the movement towards the industrialized genocide machine that pivoted around the Auschwitz proof of concept. Earlier phases included wagons with an enclosed back in which the engine exhaust was piped. The process was found to be too slow, and exposed to many service people to the execution process. The death camps were staffed to assure no-one had to interact with the prisoners and process the bodies, so no-one would have to confront the visceral reality of before and after. They were staffed so that anyone who engaged a mechanism was two steps away from the person authorizing (and taking responsibility for) the execution. The guy who flipped the switch was just following orders.

Interestingly, we'd see a repeat of this during the International War on Terror, specifically the Disposition Matrix which lead to executions of persons of interest on the field by drone strike (Hellfire missile launched from a Predator drone). During the CIA Drone Strike Programs in Afghanistan and Pakistan, the drone operation crews suffered from high turnover rate, with operators suffering from combat PTSD from having pulled the trigger on the missile launches. It didn't help they were also required to scan the damage to assess the carnage, and identify the casualties.

Interestingly, this also presented an inverted demonstration of how the human mind can tell the difference between violent video games and the real thing. Plenty of normies play Call of Duty without dealing with the mental after-effects of war, but even when we conduct war operations from continents away, our brains recognize that we are killing actual human beings, and suffers trauma from the act. War continues to be Hell, and video games not so much.