Why is so much of the city Not discussed?

Please excuse my ignorance, my wife and I have been doing a lot of research in a very short period of time. We are seriously considering visiting Houston for a potential move but have never been there and need a few trips to make that decision.

This is from bestneighborhoods.org.

I’m just curious as to why basically the entire south, east, and north of the city are never recommended. I think it is pretty much unanimous that Sugarland, Belleaire, Briar Forest, Katy, etc. are amazing. That leads to A few questions:

• Who lives in the other areas, are those locations that bad?
• How does such a small area of the city being seen as far and away superior to the rest affect the day to day life? Any other insights in this general topic that you’d like to share are welcome.

I’ve never researched a city to this extent without visiting so maybe this is common but it’s just interesting to me and I figured I’d ask.

TIA