Your contention is that GMD, THAAD, PAC-3 and Arrow are essentially expensive fireworks? Interesting. Russia and Iran will be delighted to hear that in fact their ballistic missiles were not intercepted.
While an ICBM is a ballistic missile, the trajectory is far far higher than the usual short- to medium-range ballistic missiles. Velocity at the receiving end of the trajectory will be far higher. Visibility into the trajectory will be worse, because of the huge range and the earth being "in the way".
I suspect in other contexts you're aware of this, but personal attacks generally don't land well here. Consider continuing to focus on making important points well, as that tends to work better, as does assuming the best when someone disagrees with you, since sometimes that's a sign your comment can be legitimately interpreted or read in ways you didn't expect or intend.
You were making claims that a particular technology does not work, and the other poster was ribbing you by playing along with that thought in a way that suggests the technology actually does exist and works. They did not put words into your mouth, but they did give specific examples of technology to highlight their point.