How depressing when people over-identify with their ethnicity

I am a Jew. I live in a council estate in London where considerably more than half of my neighbours are Muslims. These people aren’t my friends, but we get along fine: I pick up their parcels; we coordinate complaints to the council about the strange, blue-tinged fluid that sometimes drips from everyone’s ceilings, as if someone in the penthouse had decided to fill their flat with jelly.