I don't think they mean 'anything I don't and am not' That is waaay to general.
I think they mean things that are, IMHO cheap, ubiqitious, tacky, showy, poor quality, downmarket and in thoroughly poor and misguided taste.
Or: Pertaining to The Underclass. Should we just say that?
The trouble is every time people latch onto a work or phrase that implies a negative, unfortunate or undesirable quality, some well-meaning person urges us to desist from uttering it, as if not speaking the word will make the problem go away.
We can only ban negative adjectives and pejoratives if we ban all corresponding positive and complimentary ones, or we end up with no context. As long as it is not actually discriminatory - and it isn't, because it's subjective and hard to pin down.
It is a fact of life (we are mammals after all) that we are socially and intellectually hierarchical. That will never, never go away. If you are hoping that human beings will 'evolve' out of it, then you'll be waiting a flipping long time!
Goodness knows how you'd cope if you had to live among the Indian caste system - your poor head would explode.