That's what I got out of it too.
Obviously we would want to shoot them down if they were going to hit populated American territory but care must still be taken. Back during Gulf War 1 there were concerns and complaints about where Iraqi SCUDs were falling after being hit by Patriot missiles.
Most likely any missiles NK would launch would be unarmed anyway. Allowing one to reach American territorial waters might be a good thing in the sense that you then have clear evidence of him firing on America.
There is nothing wrong with looking at the possible scenarios.
Just as an aside...the scuds that Saddam had were poorly maintained hence the reason they were losing parts even as they launched.
The original Patriot systems weren't meant as a missile intercept weapon...they were strictly for aircraft. Their warhead was a proximity type which exploded near an aircraft showering it with shrapnel instead of making direct contact...another cause for the wide debris fields.
Since then they have developed warheads for the Patriot system that are purpose built for BMD that cut down on the pollible collateral damage on the ground from the destruction of an incoming missile.
