As you can see, the situation isn't quite like the author protrays it to be. If you click on the image, you can enlarge it.
Do you know why there are large swaths of green around the city? Because housing is cheaper. Inside the city, single dwelling homes are extremely pricey or the other extreme. People who make average incomes want to keep them. My home inside the I-610 loop was assessed at about $225,000. Down in the "green" Clear Lake area located in the southeast corner (follow I-45 south) my townhouse can be had for about $100,000.
I'm going to look at a couple of areas that include what the author of the website probably wasn't aware of. Here is a snip from his website. The two areas are circles in blue and red:
If you zoom into the area circled in blue, this is what you see:
The area in the black circle, is NOT populated. Sure, you see a fishbone design that looks like roads, but there are no houses there. Maybe there were at one time. It appears to be a giant easement area - probably part of Harris County's Flood Control Area. The issue is that this whole area is highlighted as being very low median wage. The fact is over half of it has no one living inside it.
Now we'll look at the area included by the red bracket and arrow. This is what you see:
Clicking on the image expands it and you can see that a huge, GIANT portion of the area that is labeled as having a median income of about $38,000 has very few people living in it. This entire area is 98% industry. And it is HUGE. I tried to include in the red circle all of it, but you can see I missed a lot.
The same is true for the inner I-610 around the ship channel (re:Denver Harbor/Port of Houston and Clinton Drive). The area appears to be lower median income, but in actuality about 1/3 of it is just shipping equipment and heavy industry.
This is not to say there aren't large enclaves of lower income areas. Of course, there are. North of Houston is predominantly housing with scattered heavy industry. But to call this some sort of discriminatory segregation is something of a stretch.