You have to remember that this is a WWE sanctioned book, and Flair is not going to seriously rip on the guy who signs the paycheques. Or his son in law.
He will rip on the people its safe to rip on, and praise the people who are not safe to rip on. Or at least hold his tongue.
It's safe to criticize Hart, Savage, and Hogan. And even Foley. It's not safe to rip on McMahon or HHH. I don't believe Flair thinks everything those two did was brilliant and fair.
I bet if Hogan were in WWE right now, this book wouldn't be nearly as critical of him.
It looks like an interesting read, but like any wrestling book you need to turn on your BS detector before reading.