Their over-the-top tone is kind of cute. That's about the only good thing I can say.
That book made me very angry because the information is bogus. Most of the citations are websites, and not very reputable websites.
I agree with some of the sentiments of the book, but it made me mad that the "facts" were poorly referenced. Their rant about carbs is plain wrong. The studies are showing that people fare pretty well on low carb diets. The authors are former models, and appear not to have much training in writing.
Another thing that annoyed me is that they seem to be pushing vegan substitutes for meat. I am not vegan but if I were I wouldn't want substitutes that are trying to taste like what I gave up. I'd want things that are tasty in their own way.
The main arguments in favor of going vegan were that factory farms are horrible places, the animals are treated awfully and you don't know what kind of chemicals you might be getting. To me that seems like an argument in favor of eating local organic meat. They brush off that notion by saying you can't trust anyone but if you visit the farm you can. I was disappointed that they didn't offer a legitimate reason to go vegan.
They redeemed themselves in the last chapter slightly--they said they hoped you'd get the message to trust no one, not even them. But after spending the entire book calling you names if you don't agree with them, that message is a little weak.
After reading it, I did try to eat more nuts, because at this time of year it's a little hard to get local organic meat, and I do agree with them on the point about factory farms (although that wasn't referenced any better than the rest of it). A vegan diet needs more fat & protein, and nuts are a really good source of that, nuts & fish have the "good" fats. That backfired on me as I started having some intestinal issues.

But if you don't have a reaction to nuts, nuts are super nutritious.
Good luck!