I'm not saying we can't change anything, or that these problems are unsolvable. All I wanted to express, and apologies if I failed at that, was that this isn't a security problem anymore. There's nothing to be gained by increasing security, or insisting on tighter border controls or what have you, the only way to address this is to get these people to a mindstate where hate as preached by ISIS or whatever can't take root.
But that's an unattainable goal. We can (and should) get to a point where radicals can only recruit a couple hundred people, but we're never going to get rid of them entirely. And as long as they exist, as long as they believe they can get by force what they can't get in civilized ways, there's going to be terrorism, and that's something we have to learn to live with without taking counsel of our fears and break our societies in an effort to save them.