I don't kind of believe that. Anything like this could have been a candidate for a chemical weapons carrier, which would make it an absolute priority.
An old military adage states that if you defend everywhere you are strong nowhere.
As a military commander, you have to make the choice of which of your assets are worth defending and which ones are not. This is also tempered by the probability of a target being attack. And if attack, what are the consequences (will it endanger your mission). With this in mind no one could have thought about defending a sea side mall from a missile attack. Why would an enemy waste their few offensive assets on such an attack? If that missile was headed for something with a remotely military value, it would have long been intercepted. The ones that landed remotely near the troop concentrations were ID.
Everything happens in context, especially in war.
There is also a danger of learning the "wrong lessons". Like this quote.
There's seems to be a huge hole somewhere especially since that was an outdated missile.
A whole in what? US anti-air defenses? If you really think that a single obsolete missile has a chance of getting through an Aegis defense, even in confined waters, based on this incident, then prepare to be surprise in the next war.
The other paradigm shift is that the US military is now so dominant that any infliction casualties of casualties, regardless to the cost of the attackers is seen as a "victory". It would be like celebrating the last sortie of the Japanese battleship Yamato because it shot down 12 US aircraft, and ignore the fact that the ship was lost in the process.