@Gwenfar I was a teenager when "The Spastics Society" [UK] changed its name to "Scope". I remember it well because my school cohort's first reaction was to find it hilarious that the school had had a student-published magazine called "Scope" for years, but after a while it sank in that this all implied a more serious message about the term and stigma. I think that must have been about 15 years before this book came out, so as you say there's no excuse.
I am now enjoying the book for what it does offer, but these things are still pissing me off. It feels like enough of a problem that I really can't recommend the book to people. I wish I knew how to navigate this sort of thing for myself - at this point the book is sort of a guilty pleasure.