That comment appears contradictory, because you said audio visual works are protected by copyright, then said it might constitute fair use. Why isn't this a contradiction? If something is copyrighted, how can it fall under fair use?
What a court looks at when determining fair use are the purpose and character of the use (e.g., was the original work changed to add new expression or meaning?), the nature of the copyrighted work (e.g., was the original work informational or entertaining), the amount and substantiality of the portion used compared to the whole of the original (e.g., one line in a short poem may be too much, one page in a long book might be okay), and the effect of the use upon the potential market for or value of the original work (e.g., publishing the ending of a novel could affect the market value).
A court weighs all of these factors, and more, when a copyrighted work is infringed, the copyright holder objects to the infringement and sues, and the infringer uses fair use as a defense to the infringement.
Again, fair use is NOT permission to use a copyrighted work. Permission needs to be granted by the copyright holder. Fair use is just a
defense to infringement - a “yes I infringed but it’s okay because ...” The “because” could be that the copyrighted work was used in connection with criticism or comment on the work, or was used in the course of news reporting, or was used in teaching, or was used as part of a research project or for a scholarship purpose.
As for forcing a copyright holder to defend their rights, it CAN be expensive to pursue an infringer in federal court. Many copyright holders cannot justify the high cost and have had to accept the erosion of their rights.
THAT is why the US Copyright Office has for years mulled over permitting copyright infringement suits in small claims courts. The mulling continues BUT, as I mentioned earlier, the US Copyright Office HAS added the Copyright Claims Board. The CCB streamlines the process and cuts costs for copyright holders. After years of discussions that seemed to go nowhere, this is real progress.