This is just political flamebait. If you think this is some phenomena purely constrained to cities you're being lazy at best or wilfully ignorant and driven by ideology, which is probably more accurate.
Throwing generalized insults is easy. Projection is a hell of a drug. I don't think it's constrained to cities. I hold to no ideology. I said the _worse_ of them are usually big blue cities.
As someone else so eloquently explained, this is a form of(perhaps inadvertent) bias given the comparative scale of what we're talking about.