I will say I really like Austin's terms natural, extravagant, and corrosive desires. Granted, "extravagant" may not be exactly correct, but, as it gets at the "not necessary" aspect of this category, I endorse her choice.
I'm currently on chapter 15, and I have found Austin's work spot on and fully endorse the work as a great starting point.
As for Cassius 's Kennedy misgiving, I see Dr. Austin only using his book as an example of what is meant by courage with Kennedy's book Profiles of Courage. I don't see this as political at all, simply a literary allusion.
I have completely enjoyed the book so far, and wish I wrote it myself.
Do I wish she covered some topics in more depth? Yes. Am I satisfied with how she's covered the topics she does cover? Yes!