It's always just seemed to me that poor whites are the only group that everyone feels okay about criticizing--and that goes for rich as well as poor, black as well as white. They are the last group to be impacted by the PC movement.
I guess that's why it's okay to have a "White Trash Bash" and not a "Ghetto Fab Ball."
edited to sufficiently show sarcasm and my belief that all forms of discrimination and denigration, including against those of different socioeconomic status, are wrong.