Sometimes zoning laws are advantageous. You just can't build structures like that here. We certainly have no lack of poor immigrants in NY. And tons of Mexicans, too! Everybody needs a place to live, so the poor pool their meager resources and live in "expensive" apartments and houses.(Because there is no inexpensive housing here.)
I agree with your welfare stance, though. I'd rather have the poor just move out or not be encouraged to come here in the first place, as mean-spirited as that sounds.