But dealing with terrorists that way actually means the terrorists won. They now know that you don't even have to do all that much to terrorize many and essentially bring a city to its knees, and waste huge amounts of tax money in the process. This is one 19 year old kid, not the IRA or RAF.
While this is one side of the coin, the other side of the coin is this tells all terrorists that we have a particular set of skills. We WILL find you, we WILL kill/arrest you. You WON'T get away with shit. You think the next 19 year old is going to get duped into thinking you can commit an act of terror and get away scott free?