Is it OK to make ethnic slurs about some groups of white people?

For tonight's NCAA basketball showdown between U of Kentucky and West Virginia U, I bet the Kentuckians Dennis Whittle and April Harding some West Virginia maple syrup against Dennis' bet of a country ham and April's bet of a Derby pie. Of course, some of  you are thinking why didn't you bet {insert insulting Appalachian stereotype here}?

Both Kentucky and West Virginia suffer from frequent ethnic jokes involving some combination of:

• incest
• feuds
• moonshine
• reference to movie Deliverance (which actually takes place in Georgia)

Which makes me wonder, why is still OK to make ethnic slurs against some groups of people as long as they are white? Perhaps it reflects this furious pent up demand by white people for  ethnic slurs, cruelly thwarted by the civil rights movement (also known as "political correctness" if you  were not a big fan of the civil rights movement).  I've had people tell me insulting jokes about West Virginians even AFTER they know I was born in West Virginia.

Of course,  ethnic slurs are pretty universal around the world. Latin American soccer games are famous for having fans taunt the visiting team with ethnic slurs.