Is HN one of those safe spaces where it's only OK to be racist toward white people?
Not that I think GP's comment was useful or constructive, but overreaction helps nobody.
If you can tie it to "I don't want to live near <x>," it is likely a slur of some sort.
Despite it mainly being associated with white people, I don't think it's equivalent to something like "white trash" which explicitly targets a race - "redneck" to me seems more akin to just "trashy", which is why I think it's more class-targeted as you mention.
I live in an area where seemingly intelligent people of all races occasionally mention that they think climate change is some sort of conspiracy and/or belief in evolution is a fad that will die out relatively soon. It's obviously not enough to get me to leave, but I really get why some people would have trouble dealing with that sort of thing.