Well, it's a programmed automated response so it's not like there's going to be a lot of thought behind it. NPC's have a highly enlarged and well developed amygdala. They're essentially one big nerve ending, so every encounter is processed as a threat and responded to through a fear response. Since fear shuts off logical, rational thought, only responses they have are emotional and pre-programmed. And since their programming comes purely through approved social interaction with other NPC's, their response is as predictable as the sunrise. Push a button, get a response.