It's just a reaction on the part of publishers in a publicity effort to remain relevant and sell more books. I don't know of anyone who would agree to not teach history in the sense of something that remains historical. If you change the words then it becomes something else which is the problem nowadays.
The hypocrisy is just ridiculous though because has anyone listened to the radio or watched a music video recently? It's still fine to watch or listen to songs about people stabbing each other or women getting their arses and tits out.
However yes you cannot read the words of a book which helps to teach kids the wrongs of the views from 100 years ago, god forbid. You can however listen to Eazy-G tell us how many people he's merked this week or another song about how big his knob is.
This stuff is probably why actual history won't be taught in 10 years time because people will be to scared to do so and all that will remain is the council approved dregs at the bottom. Other than that, hope, diversity and promise will be taught too despite the reality of the world being anything but that.
And we wonder why young people are so depressed, angry and confused?