The assumption is that only liberal attitudes are normal and well-adjusted: If only these small-town people could earn more income, get an advanced degree, and move to a major metropolitan area, then they could shed their chrysalis of social conservatism.
I was a lot more "progressive"-leaning before I moved to Milwaukee and was able to afford beer. I mean, not compared to DailyKos or anything--I read NRO and volunteered to help people pack when they promised to move to Canada if John F'n Kerry lost in 2004 (bastards reneged, of course...). But certainly more than I am now.
Maybe if I worked in a fashionably hip part of town with bistros instead of boarded-up windows...you can't get a latte within 3 miles of my office.