The term "ghetto" was bigoted from it's origin and definitely didn't improve by the 1940s. It was also usually applied to urban poor neighborhoods in the 1980s US and not rural ones, and frequently by people who aren't addressing population density or zoning laws when they say "urban." It does seem to me, that's it's been watered down and appropriated to a certain extent, but I'm not in a position to make that judgment call.