"heckle him for disparaging our pristine and pure sport. How dare he speak poorly of our great sport of tennis!"
I'm hoping this ironic - or hopelessly naive. You can love pro tennis (or any pro anything) without thinking it's all perfect. Is football perfect? Is the law perfect? Is there anyone who's followed tennis seriously for any time who doesn't know many players sometimes tank matches (or at least, as in the Agassi case, aren't sure they can make the 110% effort always to win - which isn't quite the same and is even commoner), for example? I found it ironic that Safin, a prize tanker if ever there was one, was so critical of Agassi. As Jon Wertheim said in his column last week, people who are critical of Agassi don't want to know the truth about tennis period, much less about him.
"All the good parts are out... so no need to read the book." That's not true either - what's out in extracts are highly selected and decontextualized very brief sections that have quite a different meaning in the context of the book.
People still carping have almost never read the book; people who have read it are almost all interested and engaged.