He has a specific point of view going in, as evidenced by his prior works, and has rather skillfully weaved the narrative around it. One would have to spend a lot of time to evaluate his narrative to find out how accurate it, and the conclusions he draws from it all is.
I think in some ways, it is yet again, an attempt to blacken America by implying we used atomic weapons needlessly.
The interesting thing for his purpose is that to some segment of the population his theory will now become "fact" simply by the virtue of it being in "print". It is a unique phenomenon we have encountered a lot in recent years. But it is hardly new. Hundreds of Kennedy assassination books and thing like water bottles and cancer show how things become fact in some populations, Simply by merit of repetition.