> That’s to say, it may be a legally permitted form of copyright violation, or it may be a legally prohibited form of copyright violation.

That's arguably not really accurate, since statutory fair use itself (and this is why it is written in a less straightforward fashion than most of the rest of copyright law) is a direct statutory codification of what the Supreme Court found to be a Constitutional limit (based on the First Amendment) on the copyright power.

Fair use is not a “legally permitted form of copyright violation”, it is the space where the federal government has no power under the Constitution to create exclusivity as part of copyright.