I’ve never been that far to the south but lately I’ve been reading and watching those novels and movies.
The prevalent idea is: in this world (Texas?) you are alone, nobody gives a cr*p about you, do not trust anyone because they’ll take advantage of you, ridicule and mock you. The world (or maybe only Texas?) is an inhospitable, inhuman, Darwinist place.
Texas is huge, and just like any other place, your experience will vary depending on where you are. Most movies use the rural backdrop as their setting. But there are huge and dense cities as well, where most people live.