My personal opinion, and things I have seen in children raised with his methods, is that Ezzo could have written the manual for how to raise a sociopath. The detachment, the emphasis on day one that the child is "not the center of the universe", and ignoring cries . . . I've read a lot of true crime over the years and there are just common factors that tend to play into sociopaths and certain things are almost always part of their past.
Of course
I also have to say that some of the sweetest people in the world were parented in less than stellar methods and continued to be the sweetest people in the world. So I do not believe that people are the sum total of how they were parented.
I do believe that there are all sorts of risks that can come into play when nature meets nurture with the wrong combination