The main thesis of the book is that National Socialism was indeed socialism, indeed of the left. Fascism and Nazisim were simply routine splitoffs which are inevitable (Hayek asserted) among socialists. Based on the public knowledge of the Soviet Gulag before WWII, Hayek predicted that very ugly things would come to light after the fall of the Nazis. You may perhaps agree that he was right.
Given that I keep seeing similarities between the Palestinians and the Nazis, and given that Nazis were socialists and so are "liberals", the connection between "liberalism" and terrorism may just turn out to be less tenuous than you suppose.
If you are so sure about this you should ask the present-day adherents on National Socialism whether they consider themselves part of the political left or not.