The analysis is wrong even if we accept the flawed premise presented (whether in US or French law).
Section 13 of the AGPL which is the one the author says is ineffective starts:
"Notwithstanding any other provision of this License, if you modify the Program, your modified version must ..."
The obligation starts from "modification" of the software, and modification of software is an act protected under copyright law. Hence you need an authorisation for it (without prejudice to fair use and copyright exceptions of course).
Section 13 of the AGPL which is the one the author says is ineffective starts:
"Notwithstanding any other provision of this License, if you modify the Program, your modified version must ..."
The obligation starts from "modification" of the software, and modification of software is an act protected under copyright law. Hence you need an authorisation for it (without prejudice to fair use and copyright exceptions of course).