Well, de facto means unintended or not official.
Segregation is, of course, the separation of the races.
The African-American and poor white area of Monroe is centered on the East End.
That, to me, is de facto segregation. I don't think that anyone planned it.
But if you were going to plan a utopian, let's-all-hold-hands kind of town, you certainly wouldn't end up with what we have in Monroe in terms of housing patterns.