Agree, and thanks for the valuable clarification! This is not a 2A-related or gun-related book per se, and hopefully I didn't come across as pitching it as such.
Rather, I'd define it as an imperfect book with a few very interesting psychology concepts, upon which people in the personal defense business could build and elaborate.
de Becker has some very good stuff---the problem with his work is that he isn't particularly consistent, and has a poor view of any singular person's ability to defend themselves. The parts that ARE really good in his work have to do exactly with what you've noted---indicators of attacks and behavior types.
Pretty much ignore anything he says about _actually_ defending yourself, but read carefully what he says about how to be aware, and what to notice in given situations.
I've given out a lot of copies of The Gift of Fear over the years.
You'll find that most people in the self-defense business (as opposed to the gun business) have read that book, and pull parts of it for use in seminars. It is actually a really good indicator to judge if an instructor teaches self-defense, or just teaches some weapon/empty hand techniques and calls it self-defense---if they haven't read this book at some point in time, that should tell you something.