You may already have seen the Chemosensory Perception paper linking poor sense of smell and high scores on psychopathy inventories.
Two speculations about this. First, moral disgust is increasingly seen as using the same structures in the brain as physical disgust, and oddly, some of the people who are most morally consistent - that is, the ones that most use reason when considering moral decisions - also have a lower capacity for disgust. Also, the same or similar genes control sexual development and smell, and both sets of structures are disrupted in Kallmann syndrome. There may be a broader link between the control of pre-rational impulsive behavior, i.e., sense-appetite driven goal-oriented behavior.