There’s a real dissonance when a self-admitted “not very good person” goes into a selfless job where one is supposed to be kind, and then writes about her pupils in a nasty way. So she’s being taken to task for being horrible when she shouldn’t have been. Teachers just aren’t supposed to write mean things about their students. I wonder why the book did so well. Maybe it was seen as refreshingly honest?
As a previous poster has already touched upon, I find it hard to understand the fixation on Clanchy's perceived niceness or otherwise.
Firstly, I don't know anyone (particularly not women, who are socially trained to be self-deprecating) who says that they're uncomplicatedly a nice or a good person. Anyone with even a modicum of self-awareness understands that human beings are complicated creatures, full of contradictions - we contain multitudes, as Whitman would have it. Clanchy is clearly a highly educated and intelligent woman, and I'd be amazed if she didn't hold more nuanced positions about her character than "nice" or "nasty".
I also don't really agree that she's written "mean things" about her students - that's so reductive, as though Clanchy is some kind of educational Regina George, gleefully recording spiteful commentaries on her pupils in her burn book.
I think she has been very honest about the unpalatable and unfair reactions she's had to some pupils and some situations, but the whole premise of the book and the structure of each chapter, is her attempt to reflect on them, taking lessons from them. This isn't being "being horrible", it's striving to understand and refine her underpinning pedagogy and practice within the context of an imperfect educational (and social) system.
Like the rest of us, she's flawed, and this whole affair suggests that there are blind spots where she wasn't aware there was issue with her responses or that there were lessons to be learned. That's possibly another pitfall in writing a memoir - it's exposing in more ways than perhaps the author anticipated.