I think it is deeper than that. Liberal communities have learned, through decades of control by democrats, that they government is their first source of support. That distances people from others in their community and so they dont feel the need to be civil. When you live on rural communities, you know the government wont be there to help and you will need to rely on neighbors. You dont want to offend those you may be asking for help. I know this because I have lived it.