If a country is protecting them, we blockade that country and freeze their assets in the US.
We are allies with most of the developed world. If we have proof that a country is harbouring a known terrorist, why wouldn't our allies support our blockade and such until such a person is turned over?
Why? Because a blockade hurts women and..of course...the cheeldrun...in those countries.
And of course...as your argument goes...they are INNOCENT people caught in the struggle.
So...you have a country that supports them and will not police them.
What do you do?
What we did.
We could have turned Afghanistan into a very large sheet of glass. That would have killed quite a few more innocent people.
Did innocent people die in Afghanistan. Yep. We had a few innocent folks die ourselves.
Now the terrorists have to find somewhere else to train...and I'm sure that the other governments in the regoion will think once or twice before they allow it on their soil.
And what...by chance...do you arrest a suicide bomber for BEFORE he's blown himself up?