But the GP’s argument was that AC is good because it made populating places like Texas possible. But was it worth it to populate those places in retrospect if it depended on a technology with known negative externalities?

Similarly, the personal automobile made urban sprawl possible. But is sprawl and ensuing car-dependency a good thing all things considered? Many would say no.

It's market forces at work with little regulation, especially in places like Houston. Real estate prices are much more appealing in places with extreme temperatures. We all couldn't afford to live in temperate climates like the bay area without some extreme zoning density regulations.

You could even extend that argument to include "is there a need for people to live in a place where they can't grow enough food to sustain their population".

I wouldn't pull too hard on that thread here, though.