The point is that deregulation of utilities increases the risk of shit breaking during or capacity being inadequate for extreme situations. And the amount of regulation to apply to utilities is most certainly a partisan issue.
The market incentivizes just enough investment to be maximally profitable in expected conditions. It does not incentivize investing for unexpected contingencies. So if electric generation and distribution is purely unregulated, you will have a grid that is not capable of providing electricity when it is needed most: to keep people warm when temperatures are dangerously low and keep people cool when they are dangerously hot.
Whether Texans would ever implement regulations to prevent such circumstances is an open question. I’m sure there are regulations on these issues, but they’re obviously inadequate for the modern climate reality. But it’s at least possible that regulations could result in a more robust grid, whereas the chances that the invisible hand guides market competitors to spend money on excess capacity and wider temperature tolerances is vanishingly small. Such investments would put providers at a competitive disadvantage for most of the year and yield very little advantage during emergencies.