You've cherrypicked the phrase "public good" and applied an out of context definition that doesn't fit. The thing being discussed was public utilities. Those are a sort of public good in the same sense that public parks, public libraries, and free education are all public goods.

The local electric utility isn't "non-excludable" (unless you ignore criminal law) but it is certainly a public utility, a natural monopoly, and public good by most metrics. The vast majority of jurisdictions regulate it accordingly.