I didn't really understand zoning until I witnessed a bunch of Southern middle-class white moms agreeing with their middle-class black mom neighbor about how they all hoped that the new construction on the [formerly agricultural] lot next to the subdivision would be restaurants instead of apartment buildings, because the latter attracts "the wrong kind of people".

Then I looked at the zoning map for the municipality, and read the zoning codes.

From outward appearances, it's to keep the poor people away from the rich people. And not just at night when everyone goes home, either. All the time, everywhere. Jobs, schools, commutes, shopping, entertainment. It's the new age of redlining, with a global substitution of bank account sizes for skin colors.

I couldn't tell what degree of intent was there, but on the ground, the zoning board has reinvented the ghetto. The poor folks get to live next to the railroad tracks. Rich folks get to live next to the zone marked as protected wetland/watershed, so that it can never be developed.