Faulkner sets his fiction in the South after the Civil War. His Southern Gothic world features a crashed Southern economy. Abner is a tenant farmer--he is at the bottom of the lowest economic class, at least for whites.
In his situation, there is little Abner could ever do to raise himself up the economic ladder. Money and jobs are scarce.
Abner, of course, refuses to play along. He refuses to be dumped on. He will not relinquish his dignity. He maintains it by avenging insults with fire--by burning barns.
Of course, Abner is obnoxious and ignorant and abusive and simple-minded (at least in some respects), and his idea of what an insult is needs some heavy refining. But still, Abner is a bit noble. A man attempting to hold on to his dignity usually commands respect from a reader.
Of course, the South after the Civil War is not the only place and time that contains people in Abner's position. I doubt that a society has ever existed that this story wouldn't apply to. The story is specifically about the South, but by extension applies to every place else, as well.