So you don't know what a Black Swan event is?
You just think you know because you know everything?
I've read Taleb's books FRiend.
In his talk, Flynn uses "black swan" as he would use the word "accident." Any accident like this is basically a "black swan." Unpredictable, non-computable, a cascade of consequences, ultimately human or system generated.
But then he turns with the comment "we can not take terrorism off the table." Yes - do not take it off the table. Investigate it first - and present clear facts for what would be a very low probability explanation.