That's a pretty disingenuous argument.
If you're in the business of providing power (or being a regulator of those providing power), then one of the things you need to be good at is predicting demand. You should be able to model various kinds of weather scenarios and their impact on electricity demand, and find out what the worst-case scenario is, and roughly how likely it is to occur. And then you can plan your capital expansion plans to be able to meet that future demand.
So if supply is struggling to meet demand, there are three possibilities. First, supply could be lower than forecast due to unforeseeable circumstances. Second, maybe things were worse than you forecast, and demand was unexpectedly high. However, we appear to be in the third possibility: you knew that supply was insufficient to meet demand, and you didn't care.
Texas seems to be regulating its grid to ensure low prices above all else, even at the expense of reliability of the electrical system. If you need 1000 MW of spare electrical generation capability, you need that whether your grid is mostly based on solar and wind or whether it's based on gas and coal. That the complaints are directed against renewables are I think because the renewables are undercutting fossil fuel plants, and the state is too cheap to ensure reliability--and the renewables are a more politically convenient scapegoat than the bad regulatory oversight currently in place.