I've thought about this a few times myself.
I think that people in rural areas tend to be much more in touch with nature, and nature, itself, tends to bring about an appreciation of and respect for a creator, making us much more amenable to accepting that there are moral laws, as well as natural.
The choice of where one lives, as well, might indicate a certain amount of ruggedness or independence - or lack therof.
On the flip side, urbanites really do have some values as well, but they are based much more upon relationship, as these skills are important in a large city.
This overvaluation of realationship based values might make one much more inclined to dialectical thinking, which had it's roots in socialism to begin with.
That's about the best way I can figure it.
Alternatively, maybe city folk are just all messed up. Why else would they opt to live in such cesspools to begin with?
Well, Griz, I can only speak for myself. But I was born and raised in Los Angeles ... since the 40's. And it is not a cess pool.
There are terrific advantages to living in a big city ... and a down side. As there are advantages and a down side to living a rural life.