Yea it's lower class to upper class, non-racial, even upper class humble to upper class snooty where I'm from. I did some research, and the origins of the word uppity is racial (
Online Etymology Dictionary), but I also found forums where people also expressed that they had never realized there was a racial connotation to the word, both in response to the current discussion we are having and to earlier discussions. The word 'Uppish' with British origins seems to be the exact definition that I see 'Uppity' as. Online dictionaries don't note the racial connotations, but that's not surprising. I guess the word has just lost that connotation in some communities.
I would like to note that the community that I learned this from is in the south, very close to Georgia so perhaps it's fairly regional?