I don't understand what you mean by "all his arguments held back then" when a significant portion of the book explicitly shows and discusses data regarding the number of wars fought during 1800 and before, compared to 1900 and early 2000. And the fact that another significant portion of the book deals with data about how much more likely a person is to die from violence in general during that period compared to the more recent period. I'm still convinced you have not read the book, and I suspect that is why your counterargument to it resembles a strawman.