The problem is we have a culture that often overly accepts protectionist and defensive systems and is highly averse to any risk what-so-ever. When these sorts of systems are put in place, they become far more difficult to remove than erect, even if they're shown to be ineffective, wasteful, or actually add to risk.

You're not going to see many politicians vote against such systems because the second some incident occurs, their stance against protectionism will be crucified by opponents and gobbled up by the general public. This is one reason why the US defense budget continues to balloon. Anyone who pushes to reduce spending can easily be painted to the masses as someone who doesn't care about or want to secure your safety. This dynamic also plays into use of fear for power, so those in power drum up fears and explode risk in their own interest.