The underlined part of your quote was EXACTLY what my dear white Momma meant when she told her white children "Don't you get uppity with me!" I just had no idea it was a "charged" word, until, like I said, I saw that old episode of Benson.
I agree with the other poster who thought it was a shame that the word had such a bad rap, because (racial overtones aside) it's really pretty unique and conveys a very specific meaning.
"Those trailer trash Clintons got all uppity and thought nobody would mind they stole that furniture from the White House."
BTW, thank you for the history behind it.