Travel Ban Arguments: Most Foreign-Born Terrorists Radicalized Years After Coming To U.S.

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   Ok, not to be accused of supporting anything Trump-related, but...how is this an argument against a travel ban?
   I mean, it could be part of an argument, if other premises were added...but...by itself? Why does it matter if it takes, say, 10 years for some dangerous proclivity to manifest itself? One could still argue that we're doing something like importing raw materials for bombs that will be used against us.
   If, say, rates of terrorism were much, much higher among Muslim immigrants, then, even if terrorist tendencies didn't manifest themselves for ten years...would the time-lag matter for purposes of determining immigration policy? And if our question is, specifically: Do we need more stringent vetting procedures?...does the lag matter?
   If we were considering whether to let in people infected by a virus that commonly caused a virulent, contagious disease ten years after they entered...would the lag matter?
   Again: yes, I do realize that these problems could be fixed with additional premises/evidence...but if we're supposed to accept this argument, then those premises have to be argued for.