It may be privately owned, but regulatory control still exists, and prevents the scenario you're talking about. To the extent that the regulatory scheme fails,

It may be privately owned, but regulatory control still exists, and prevents the scenario you're talking about. To the extent that the regulatory scheme fails, that is a problem when and where it happens. But I've never heard of a power company refusing to provide electricity to a customer due to political disagreements. At least not in the U.S.