"Redneck" isn't immediately derogatory like nigger and kike are. Redneck can be used to imply more of a lifestyle than a race, while you can be redneck and white (And that's generally what's implied) you could also be a redneck and Latino for example. For those reasons redneck isn't on the same level as nigger or kike. If they said "Cracker" then it would be a different story but they didn't.