Possibly they agree because it is true. The vast majority of those who adhere to the Islamic faith in the West are not violent fundamentalists and they no doubt just wish to get on with their lives in peaceful coexistence with other faiths. However, let’s be clear. A small minority across the world embrace beliefs which are profoundly antithetical to western values and they also believe that violence is a necessary path to achieve them. When you have hundreds of millions of participants in the faith even a small minority  within this group presents a significant threat to the west. Sam Harris paints this challenge very clearly. And so if I were a member of this faith I would put this problem on the top of the agenda with my co-religionists to resolve.