Edward Sumner Grant at several points of the story espouses the philosophy of Nietzche and the Ubermensch. Grant sees his spree as a way to seize control of life, to find meaning in himself. The evolution of his methods mirrors the self mastery of the Ubermensch, and likewise his removal from society to the bayou shows independence. This game argues that the philosophy of the Ubermensch is fundamentally flawed as it fails to account for the a priori knowledge inherent in all people which affects their worldview. No person can be truly removed from society, achieving true solitude, because all human life exists in a social context; There is no child who has never had a mother, no baby which survives without a guardian who teaches. 

The disparate oppressed communitites of 1950s New Orleans make up most of the Cannibal's victim list. Pham is a homosexual, Pinnick a communist, the Brownes are Mexican immigrants, etc. Throughout the investigation, the players were forced to navigate these complex group power dynamics (in a fashion very similar to Clarice Starling in Silence of the Lambs) in order to follow leads. Grant kills people who were already under attack by society as a whole. Why is it morally wrong for him to do so, but acceptable for the society to similarly target these communities? Why does the world care more for their rigor ridden corpses than when they were alive? The answer, according to this theory of sociology, is that the dead no longer stand a threat to the dominant group's resources and power.

Every main character in the Crescent City Cannibal rejects societal norms in their own way. LeBlanc does not play by the law to get justice, Lasse is a woman in a vastly male dominated world, Stewart is a transvestite, and Hoover is pushed out of his life in Washington D.C. and considered an outsider wherever he goes. Finally, Grant rejects traditional morality as defined by society, following his own code of conduct which permits him to revel in cannibalism and violence.  The 1950s setting of McCarthyism perfectly accentuates this theme by creating an atmosphere of paranoia in news and daily conversation.

A great many witnesses are interviewed in the course of the investigation, yet very few are called to the stand. The bias socially implicit in certain racial, gender, and class distinctions is a constant concern for the detectives. At several points, witnesses were critically examined and compared with others to find corroboration or contradiction. For example, the testimony of Laura Pinnick and her nosy neighbor was too biased to take alone, and the testimony of Jebodiah Epstein was likewise, but because they overlapped on a precise description of the killer's car, they were able to ascertain "truth" from bias.

The return of so many veterans from WWII created a large population of young, working men with severe PTSD and other mental disorders. This population is represented accordingly in the game, with different characters presenting variable perspectives. Grant, for example, feels liberated by his wartime experience, whereas others, like Driscoll and LeBlanc, see it as a neverending burden, to live life for those who died. 

Genetic mental illness can also be seen as a cause for criminal/deviant behavior, such as for Jeffery Allen Driscoll, a schziophrenic, who mistakes people around him on occasion for Germanor Japanese soldiers in disguise, and reacts violently. Similarly, William King was genetically predisposed to alcoholism (as was his brother, the victim Albert King), and it caused him to get into frequent barfight. William King also had great difficulty functioning in daily life due to frequent depressive episodes. 

Daniel Louis Armstrong is written to be a psychopath, exhibiting drug abuse, lack of empathy, excessive retribution for minor inconveniences, and more. Yet, he is not involved with any violent criminal activity, because psychopathy does not necessitate such. 

In all the cases of mental illness in this game, genetic or otherwise, it is clear that the same mental factors which cause emotional instability and criminal behavior also cause a person to struggle to effectively operate as a serial criminal.