I'm surprised, considering how South Carolina's state flag looks like the welcome mat for terrorists:
Seriously, folks; the slow inundation of illegals from terrorist-harboring countries has been known and suppressed for years. They get trained enough to pass as Central/South Americans then scurry for their pre-arranged mosque points. The FBI is ordered to track them but cannot pursue them after they've gained "religious refuge" (lest the ACLU lets the whole cat out of the bag with a revealing lawsuit).
Why, you may ask, if so many are already here why haven't they made any significant attack? Partly due to the "Easy Chair Syndrome" - U.S. culture is mind-boggling and seductive to those raised in ignorance and hardship. I suspect the majority get here, look around closely and say to themselves "Screw the Imam's orders...I'm getting me a piece of this!"
PBS aired a documentary last year where a former Palestinian's family came over to live with him in New York. The matriarch was non-stop on Jew hatred and trying to shame other NYC Palis into a jihad against the Jews. Local boy gave up on the crazy witch and sent their butts home.