I think they may misunderstand his position with the "extravagant desire as a surefire happiness-squisher."
They probably haven't read Living for Pleasure yet.... Although I quite like the use of the term "extravagant desires" in that book, this does point out the problem with that description. For now I would give these authors the benefit of the doubt and assume that they're using "extravagant" to describe unnecessary desires.
And yes, it's nice to see that they understand the difference between desires and pleasures