I believe he was born here,...by the way...just adding that fact to keep facts correct.
He didn’t say the shooter was an illegal alien. He’s saying the shooter worked for G4S, a company which is transporting illegal aliens into the country.
So IOW Mateen could have been using his job to help smuggle in jihadists with whom he might be acquainted.
BTW, has this been called to Trump’s attention? These are outstanding dots when connected.