They're not saying don't charge it at all - that's merely your cherry-picked info to fit your narrative.
What they're really saying is don't charge during peak demand hours, it's like a 3-4 hour window out of 24 hours. And only in the summer. Many states do this already and have for years. And most EV owners charge at night anyway.
But go on with your half-baked theory...
edit: just looked it up; they're saying don't charge from 4-9pm. Also it's not mandatory, it's voluntary. And in CA it's also the power company that's asking, no different than in your state. You should try getting your facts straight:
Source
It's not solely about the power delivery, it's about the strain on the grid during peak demand + heat. I don't care if you had fusion power - transformers still blow in heat. Lines are still stressed.
That's why even 20+ years ago in AZ they were asking people to watch their AC usage during certain hours; even with nuclear power.