You know, at this point I have to question whether or not the komarisa actually understands that the dolls she was stabbing were, in fact, NOT actual humans.
Depending on how the mother introduced the whole concept of 'human extermination' to her, does she even have the ability to distinguish actual humans from dolls?
In a way that tends to happen a lot, not only with "human extermination" but with other games or fantasies yu's haves, like how some ko's think they are the strongest or best hunters just because in their games they do well.
It's more prone to happen to Marisa types, because they have that delusion of being the strongest as part of their identity. Scum Marisa usually think they can get everything because they're strong enough to deserve it. Everything else should obey them because of fear to that strength.
Reimu types in the other hand is the "so you want to raise your hand to a woman ?" while stepping on the husband kind of character. They think everyone should be "kind" to them and that they deserve to do anything and get everything they want because they are... well, what they are. Letting them take it easy is an obligation (else you're a scum). It's a privilege that's as natural as gravity pulling things downward.