When someone asks about the term redneck, my pat answer tends to be - well I prefer the term Springer-ite...
Is the term redneck racist? The vast majority of rednecks are white, I don't think Al Sharpton is going to take to the streets protesting the word.
Is it a slur? I don't know... It's an insult for sure... but it's probably an insult based on what ever a person's own definition of redneck is...