When the DHS knows there’s an active terrorist running around, they’ll pull out all the stops and deny the guy’s green card application. Other than that, the guy is free to work and roam and gather resources and bomb a public place.
While on the other hand, the FBI is out finding an aimless, impressionable hobo without any resources whatsoever, egg him into doing something grandiose, give him money to buy supplies and introduce him to suppliers from whom to buy explosives, help him plan the whole thing, then swoop in and arrest him in the act.
So on the one hand, the feds know there’s a possible terrorist running around and do nothing about it, while on the other hand, they create a terrorist out of whole cloth in order to stop him in the act and claim victory in the War on Terror.
What are we paying these guys for again?