Seems like virtually all the talk above is about non-citizens who are perpetrating violent acts, either on or outside US territory. The article's first sentence (which admittedly is lost in the overblown rhetoric that follows) seems to make a good point; U.S. citizens who are Muslim aren't any more radicalized or violent than a host of other groups: Puerto Rican separtists, white supremacists, extreme Zionists, Communists, and so forth. Considering that I live in a region that had a host of church bombings from the 1950s through the present (series of arsons done recently by white supremacists), a region that had a century of lynchings and mob violence, the data presented would seem to jibe with anecdotal evidence that the KKK has done more individual acts of what today would be called terrorism in recent years than any American citizen who follows the precepts of Islam has caused.

Of course, one could look at it from the basis of percentage of membership, but that's not what the article or the debates above focus on, no?