Not wanting to be too PC, but your list would have worked better for me if you had placed the names of other ethnic or racial groups that correspond to the designation "white trash" instead of just the ethnic or racial or sexual orientation name - i.e. "getto" instead of "black", "Euro trash" instead of European, "baja classe" instead of mexican.
What your list communicates is that just by being black or mexican or gay, people correspond or are similar to lower class white people. Not a huge deal, but you could have made the joke better. It's like "one of these things is not like the others..."
I see middle and upper class white people jumping lines all the time. Mostly at Six Flags parks, but whatever.