The claim that governments are not stopping terrorists is ridiculous. There are people who are sitting in jail right now who have pled guilty to plotting terrorist attacks that were prevented. No, you can never stop all terrorist attacks, but that is a poor reason to not bother preventing others. You are free to argue that current surveillance practices did not actually help prevent these attacks, or that additional regulation and oversight is necessary, or that you'd rather have the terrorist attacks than any surveillance, or that terrorist attacks are really the fault of some U.S. policy that should be corrected, or whatever else you want, but whatever you argue you really should not just avoid reality and invent your own.