He disagrees with the idea that traumatising children is retro, or with the causation vs causality? It's been a few years since I read the book, but I had his do() operator in mind when I wrote the comment.

Edit: Okay - I clearly have to clarify my comment. Intervention studies are not retro. Studies in which you deliberately traumatise children, however, went out with Ceacescu. I was making a joke (albeit apparently a poor one).