...is that the urban centers...which are vastly democratic...have generally seen the benefits of massive federal programs. They also see more of the negative aspects of capitalist society...poverty, poor education, etc...

The Democrats have made these "their" agenda items. Not that the Republicans don't address these issues...but they generally address them by wanting to provide more local control...and the Democrats have used that as the wedge..."You SEE, Virginia...those evil Republican bastards don't care about YOU...they don't want to deal with your problems...WE'LL FIX IT FOR YOU"

The difference in mindset is that the "country music belt" WANTS to "take care of their own"...and the city folk want somebody to take care of it for them...

This is, of course, a vast oversimplification...but if you have to nutshell the argument...this is probably a good start.