That is essentially the author's point, though. Society has endorsed powerful private institutions (specifically in his book, universities) that have moved away

That is essentially the author's point, though. Society has endorsed powerful private institutions (specifically in his book, universities) that have moved away from the Enlightenment-era's notion of radically protecting freedom of expression. Instead, this freedom has been relegated to mere legal protection and the spectrum of speech protected and amplified by private organizations has significantly narrowed.