Earlier quoted context omitted.
Note to readers: If you're not from the US and confused about the 20 degrees (I was), note that it is Farhenheit and not Celsius! So around -6°C, which is of course very cold! (edit: when you're on the internet, better to specify which unit you use, your audience is international)
I mean -6°C isn't very cold either. Its not every year you see temperatures like that, but its also not exactly uncommon. We had -17°C (1.4 °F) and lower here in Germany. We had some problems here and there, especially the railway, but afaik there were no major problems regarding power outages and heating. But obviously we're much more prepared for temperatures like this here.
The power is out - there is no heat. For a lot of folks, this is more akin to camping without proper gear, during the winter, and without a fire.
There isn't much infrastructure to deal with snow and ice, either, nor are most folks going to be prepared to deal with frozen pipes.
The folks in Texas don't have the same sort of house insulation either: Since it doesn't get that cold, but it does get hot, the houses are designed to keep the house cool. And since this cold is very rare, folks aren't likely to have actual winter coats. What makes the cold tolerable for me - in Norway - is that I'm fairly prepared for it. They aren't.
-6 is really darn cold for the unprepared.