While the parent post was probably referring to this figuratively, when we think of something repulsive we actually activate the same part of the limbic system in brain that we use to feel repulsed when we smell something rotten. In a way, our frontal cortex is hijacking the legacy "run away from smelly stuff" system instead of recreating it from scratch. This also extends to other systems as well: when someone is "hungry for success" they are using the same part of the brain that makes you hungry for food.