"If the US and allies could take down a rocket they'd shoot down every NK test missle just to make a point."

I'm not sure that news is true, shooting down a missile with something that doesn't fly and is not a laser would require an immense power, but anyway, using it on test missiles would be a really bad move: if you have a countermeasure you never use it until when it's really necessary (war) both to keep the surprise element and to give minimum information to the enemy about what you can or -even more important- cannot do.