Alternately, it's a holdover from a culture of honor, where violence not sanctioned by institutions was encouraged because institutions were weak and the way you kept yourself, your family and your stuff safe was to have a reputation for violence. (The article I linked to isn't great, but there's some kind of unrelated Christian use of the term "culture of honor" that crowds the Google results and I couldn't find any survey papers.) That's regressive too in a modern context, but it's not the same as fascism. A fascist superhero would be backed by institutions, fascism being all about gaining power by surrendering to the collective, hence taking its name from the fasces.
That article links to a straight up bullshit study. Cortisol levels take weeks or months to crest. They take fuckin' 10 minutes just to test. Delaware?Participants were 83 University of Michigan white male undergraduates (42 northern, 41 southern) who were recruited by telephone and paid $5 for their time. Students who had lived in the South for a period of at least 6 years were considered southern. The South was defined as census divisions 5, 6, and 7. This includes the states of Delaware, Maryland, West Virginia, Virginia, North Carolina, South Carolina, Georgia, Florida, Kentucky, Tennessee, Alabama, Mississippi, Arkansas, Oklahoma, Louisiana, and Texas.