I imagine it's something along the lines of "Kill them or we kill/torture you/your siblings, etc." And parents, loving their children and not wanting to see them killed, telling the kids that it's okay would logically occur at that point... Then they're trained, brainwashed to be brutal killers... They're only children, after all. :(

It's not that far removed from what the Nazis did, forcing parents choose which child would die right then or they would kill them all. It's just sick. Some people deserve to die bloody, horrific deaths.