Thank you for the question.
The book provides an interesting perspective. Many western researchers examine the phenomenon from a western standpoint, including the growth of Jihadism and right-wing extremism.
To answer your question about the far right, I believe that one common mistake is to see the far right as if it were something that goes back only a few decades, as a form of neo-Nazism that advocates violence and the overthrow of institutions. But the far right has evolved. Today's far right includes people who wear a suit and a tie. Also relevant is the fact that the United States has managed to create an "alt-right" that has transformed its political discourse. For example, there has been a shift away from racism to culturalism. Rather than saying that one race is superior, it's now one culture that is better than another. My colleague put it very well earlier when he addressed the issue of white nationalism.
There is also a lot of victimization. The argument is that the white majority, in a reversal of history, is threatened by immigrant populations and other cultures. You are no doubt familiar with the conspiracy theory about the great replacement. What we're seeing is the same kind of argument in a more polished form, by which I mean more politically correct.
Another important factor is that the far right movement always claims to be defending people against the elites. These elites are you, us, the researchers, and, of course, the mainstream media. The tone of the far-right agenda is now much more populist.