This feels like bait for a class warfare flamefest, so I'll be a devils advocate here.
Is there any evidence that some shenanigans was afoot here? Is it possible that they had a backup system?
I don't know the full set of details, so it is possible there is no shenanigans. I did my best research, and found that Highland Park receives electricity from Oncor like the surrounding areas that don't have power. As for a backup system? Everyone is on the same grid. I suppose there may be a higher percentage of homes in Highland park with solar, but I've never seen solar roofs when I drove through Highland park