You could confirm or deny whether or not you have actually read the book, having presented yourself two posts above as someone in a position to critique it. Is misrepresentation of expertise and talking past the people you're responding to not also a low-effort, bad faith act?
It seems pretty obvious that I have read the book if I have an opinion about it. I don't start asking whether you have finished high school and whether you passed any reading comprehension or IQ tests. I think such questions are insulting and they don't lead to a fruitful conversation.