He didn’t start out by shooting mothers and children.
He started out in elementary school, being taught that evil people were keeping him and his countrymen down. They called them Jews back then.
Today we call them 1%ers, rich people, or white oppressors.
There were a hundred little steps between that and shooting babies because “nits make lice”...
“I often wonder, how can anybody do that, shooting a defensless mother and her child.”
The victims were first dehumanized for a period of years as traitors, degenerates, subhumans, parasites and the enemy within, or just over the border. Just as the Federal government and the Southern Poverty Law Clinic have been doing about ‘right wing extremists’, ‘racists’, ‘Dominionists’, ‘militias’ etc. for some years now. Only when that has traction do the actual assaults begin, culminating in liquidation if it meets with complacency and opportunity.
Once you dehumanize a target demographic, liquidating them is just pest control. The ‘authorities’ also get the ball rolling with sociopaths doing the wetwork initially. Later on, the weak and susceptible are trained into the tasks. If they can’t handle it they are moved on to other duties, or discharged. Peer pressure and the human default setting for conformity makes the dissident a rare breed however.
Both the Bolsheviks and the National Socialists got their initial armed sections up and running with a mixture of no limits fanatics, common criminal who were in it for the thrills it offered, and resentful scrubs. The opportunities for rape, loot, prestige and recreation or other perks were offered as rewards. There is an abundance of people in this decayed society who would be up for the task, and a whole world to import them from as well.
There is actually a large amount of scholarship out there on how ‘the unthinkable’ actually is very thinkable, and with the right circumstances and timing, very doable. See for example Robert Conquest, whose area of expertise was specifically the Soviet Union. The similarities in other countries though - Spain, Germany, China, Turkey, Cuba, Nicaragua, Cambodia, Iran, Iraq, Lebanon, Somalia, Sudan etc. show it to be a reliable and cross cultural set of techniques though. Since it ain’t broke, the tyrants of the world don’t fix it.