I find the way language is being exploited and twisted to support an ideology quite sinister.
KC deliberately and maliciously told lies in order to start a hate campaign against someone who's opinion she found offensive. Evoking #BeKind within the context of abuse and censorship feels rather disingenuous and to be creating a potentially dangerous precedent.
Telling someone not to lie is not telling them to #BeKind.
Similarly there is a huge difference between making sexualised comments about children, and "noticing that a child has a very sexualised appearance".
There's absolutely nothing in the specific comments people found worrying to suggest the children in question had a "very sexualised appearance" - unless you believe that possessing breasts or legs is inherently "very sexualised appearance." At one point KC makes sexualised comments about the body of a girl who wears a full hijab!
(Obviously there are other parts of the book where KC does comment on how her students dress, but those are different comments. The passages people have flagged as inappropriate are the passages where she randomly comments on a child's breasts, or talks about how long and shapely a child's legs are. There's absolutely nothing to indicate the children whose breasts and legs KC notices have "a sexualised appearance".)
It's pretty slut shaming and victim blaming to claim it's fine to sexualise a child because of the way they're dressed (the "they were asking for it" defence so commonly used by male predators) especially when there's no evidence they even had "a sexualised appearance" in the first place.