Again, as IDont said loook at the context. We now know that the Iraqis had NO WMDs. It is quite possible that that fact was taken into account. However that is going down too many rabbit holes and through too many looking-glasses, if you know what I mean.
You cannot use historical hindsight and apply that to a situation. A SAM battery commander should not be in the position nor part of his duty to second guess if incoming missiles are equipped with WMD or not. In fact, at that time, it is widely presumed that the Iraqis did because gas masks were being handed out to infantry units.
I however tend to agree with IDont. It seems to me more likely that the US radars detected the incoming Seersucker, it was determined the that it would land in the ocean and the commander in charge decided not to fire and waste a Patriot. However the calculations were off and the missle landed on the shoreline.
Then your tracking systems must suck even more because there is quite a big difference between a missile heading to a city and one heading to the sea. If your tracking systems cannot tell the difference of one and the other, then how do you expect it to intercept at all?
Bring these arguments to a court of inquiry and you are signing a career deathwish.