It depends on your definition. In Australia, the term does have that meaning and no other - and the "bigot" part specifically includes racist. Here, it's because many of the "white" settlers had pink or reddish skin due to being fair and flushed in the heat or sunburned. Much more common with Scotts descendents living in rural areas. Quite often their necks are literally a crimson-reddish colour in the heat. The term "redneck" can thus be a racist term of abuse in that it assumes that all people who happen to have red necks are racist, ignorant and dull or dumb. Naturally, appearances are no predictor of internal traits.
I believe there are several different meanings in different parts of the world. One US woman told me that, [in her area,] it just meant a working man or labourer who wore a red handkerchief around his neck.
Of course not, but the living conditions of rural areas do tend to keep people ignorant. That's why rural areas tend to vote Republican. Which is too bad, because redneck culture is pretty fun. I almost died mudding, then chose to do it two more times.
@BackyardShaman There's this guy on here called redredred that's insulting my native American spirituality and cultural of way of life of connecting with nature.