A personality type which is incapable of processing a broad spectrum of thought and only perceives issues in an all-or-nothing black or white context. Closed-minded. Obtuse.
That's a really abstract concept, but you may not want to tell Joe about it. He's pretty monochromatic and won't get it.
Consisting of one color or hue (or race). Used by liberal elites like the NY Times to deride communities that are racially homogeneous, whether or not that was by design, coincidence, organic growth, or ethnic clensing. This is a tacit accusation of racism towards those residents. It also puts a halo on New Yorkers who ride on mixed race subways while residing in racial, economic, religious, ethnically pure enclaves fiercely guarded by co-op boards.
The housing developments of Alpharetta, Georgia are largely monocromatic.