Frankly, I suspect a lot of whatever Izutsumi's malfunction is has less to do with being a catgirl who's more cat than girl and more to do with being seventeen.
marcille, confronted with boiled mushroom: ewwwww it was just up and walking arooouuuund
marcille, confronted with her best friend's skeleton: [etching an evil necromantic circle into the ground] the concepts of "right" and "wrong" were crafted by empires of men to shackle and puppet us